Curséd Fruits

Curséd Fruits (呪い実, Noroi Mi) are mystical fruits found in the world that can give the eater many different and varying kinds of strange and interesting abilities, depending on the type and variation of the fruit itself.

There are some seen only in the anime and different ones seen only in the manga. However, most of them appear in both and are crucial in the storyline where many main characters possess their powers.

According to Oda, a "certain professor" will explain the complex mechanisms behind all of the Curséd Fruits in the series in the near future.

"."
 * —About Curséd Fruits.

About
"They say the Curséd Fruit were created by a mysterious entity known as the "Creator of the Sea". That who ever eats it, gains one of its amazing and special abilities, but the sea will turn against you."
 * —Rex speaks to Buggy on Curséd Fruits, while talking to Shanks and Teech.

Curséd Fruits are said to be the fruits of the Creators of the Sea and that the secret to their power is hidden in the Grand Line. Because encounters with them are rare (especially outside the Grand Line), a number of rumors about them have risen, making it difficult to tell whether some things are fact or fiction. The average person knows nothing or very little about what they are or what they do; this especially applies to people in isolated countries, even within the Grand Line, such as those of Amazon Lily and Wano Country, and even Princess Shirahoshi of Merman Island, as none of them know about Curséd Fruits, instead believing the powers bestowed to be curses or sorcery. Because of their power, if sold they can expect to fetch well over 100,000,000 berries, and Curséd Fruit users themselves are sold at market prices as slaves. Of course, individual fruits each have their differences in price, dependent on the powers bestowed, as the Op-Op Fruit is worth 5,000,000,000 berries in the black market. There are more than 100 types of Curséd Fruit.

One running theme with Curséd Fruits, however, is the fact that they taste unimaginably bad, to the point of making it seem like the user had taken poison. The Curséd Fruit, when consumed, gives the consumer a power or special trait, which they will immediately become aware of; a person who has eaten a Curséd Fruit and gained its powers is known as a Curséd Fruit User (能力者, Nōryoku-sha; literally meaning "Ability User" or "Esper"). The fruits come in all different shapes and colors, and all Curséd Fruits presumably have swirl marks or patterns on them of some kind. The only known exception is the Curséd Fruit made by Vegapunk, which had ring patterns on it. There can be only one of each type of fruit at a time. Only one bite is needed for the user to gain the power of the Curséd Fruit, after which the Curséd Fruit becomes a simple, useless, disgusting fruit. Despite this, all users tend to eat the entire fruit, as they are apparently unaware of this fact. Swallowing the fruit whole, as Buggy did, has the same effect. Peeling off the skin and eating it piece by piece, such as Kaku and Kalifa did, also works. After ingesting the fruit, the powers within affect the eater's lineage factor.

Curséd Fruits are the origins of the powers of some of the strongest people in the current generation of the world, including rookie pirate crews, Navy admirals, Seven Warlords of the Sea, and at least one Emperor. They are common in the Grand Line compared to the other four blues. A typical Grand Line Pirate crew will often center around a captain with a curséd fruit ability (such as the Bellamy Pirates, the Wapol Pirates, or the Foxy Pirates), while stronger crews and organizations will often contain many Curséd Fruit users (such as the Whitebeard Pirates, the Don Quixote Pirates, Baroque Works, or the Navy). In fact, since entering the Grand Line, nearly every single major opponent that Luffy has faced had a Curséd Fruit ability, while in the East Blue he only faced two (not including Alvida, who ate her Curséd Fruit later after their encounter).

Like many series, One Piece follows the trope that a Curséd Fruit power also generally affects the clothes that the user is wearing. Paramythia fruit users alter their clothes along with themselves automatically (for example, Luffy's shirt will never burst a button when his chest is swollen in Gear 3rd, Mr. 1's pants become blades along with his legs, etc.), Zoan fruit users' clothes will fit in the same proportions after their transformation (Chopper's hat grew big when he was in Monster Point, Jabra's shoes are considerably stretched when in the hybrid form), and Logia fruit users transform their clothes (and subsequent accessories) to their element along with themselves. Oda explained in a SBS once that if he had done it realistically, the manga would have too much unnecessary nudity. However, some users do not seem to adhere to this, such as Bonney Jewelry and Honey Queen, whose clothes do not change proportionally to their powers.

It is implied that this common trait can also be extended drastically, after Curséd Fruit powers have been "awakened," where the powers would not only affect a user's clothes but also their surroundings, as demonstrated first by Doflamingo when the String-String Fruit affected everything around him.

Superiority and Unpredictability
"Depending on how you use and train the ability of the Curséd Fruit... It can become a strong weapon in battle."
 * —Crocodile's statement on his Curséd Fruits powers.

As noted by Crocodile, there is no way to tell how Curséd Fruit powers will fare when pitted against one other. A Curséd Fruit user who normally dominates all other powers can sometimes be brought down by a power considered "weak" in comparison; one such example is the Gum-Gum Fruit unexpectedly withstanding the Rumble-Rumble Fruit's powers and the Wax-Wax Fruit unexpectedly holding back the Venom-Venom Fruit's powers. Another surprise also came when the Flame-Flame Fruit clashed against the Smoke-Smoke Fruit, equalizing with each other, and then later against the Ice-Ice Fruit with the same results. Some Curséd Fruits of similar powers have been confirmed to be superior over another, though this in no way means that the superior ability user is stronger than that of the inferior's. Confirmed superiority powers listed as:


 * Mag-Mag Fruit (Superior) - Flame-Flame Fruit (Inferior): Forms of heat, Magma is of a higher order than fire.
 * Ton-Ton Fruit (Superior) - Kilo-Kilo Fruit (Inferior): Body weight, The increase in weight by metric tons, which is 1000 kilograms.
 * Ice-Ice Fruit (Superior) - Snow-Snow Fruit (Inferior): Frozen states of water, Ice is a more effective freezing agent than snow.
 * Arms-Arms Fruit (Superior) - Blade-Blade Fruit (Inferior): Blade production, The Blade-Blade Fruit is limited to gain blade characteristics on one's body, while the Arms-Arms Fruit can create bladed weapons, along with a variety of other weapons.

Curséd Fruit powers are so varied and mysterious, that the powers gained from eating one can serve purposes that may transcend normal limits. Such surprising effects that Doflamingo Don Quixote believes he may find one to save Law Trafalgar from the reputably incurable Amber Lead Syndrome, showing that he places more faiths in a Curséd Fruit of such power than in medical science that failed to find a cure.

Awakening
Curséd Fruit powers can, in rare occasions, be "Awakened" (覚醒, Kakusei), increasing the abilities of the user. The details of how a Curséd Fruit can be awakened are so far unknown, but the increased abilities have been seen to allow significantly more power, as well as new abilities. The effects of the awakening depend on the class of the Curséd Fruit.

For Zoan-class powers, awakening grants the users much larger transformations than other Zoan, while also gaining even more physical strength and durability, the latter contributing to a higher recovery rate. The Jailer Beasts of Impel Down are all awakened Zoan users.

"Listen up, hatchling. Curséd Fruit abilities have a whole other stage to them. It’s called "Awakening"! Very rarely, an ability will "awaken", and begin to affect things other than the user's own body!"
 * —Doflamingo Don Quixote to Luffy D. Monkey on the new power he is displaying.

For Paramythia-class powers, awakening can allow the power to affect even the surroundings, as opposed to the user's own body. Doflamingo Don Quixote, with the String-String Fruit, is confirmed to have awakened, and can transform objects to string as well as augment his main ability to create string from his own body; Luffy commented that such a feat makes it appear that it is no longer a mere Paramythia.

Identification
"We can figure out the name of a fruit by the power it gives, but the kind of power we get is completely up to chance."
 * —Kaku on his and Kalifa's unidentified Curséd Fruits.

According to Oda in a SBS, the same power of a Curséd Fruit can exist more than once, though no two Curséd Fruits of the same kind may exist at the same time. Several Curséd Fruits have seen their consumers either die or meet unknown fates within the storyline. Whitebeard's Tremor-Tremor Fruit is still in use despite his death because Blackbeard somehow assimilated the power into himself, while Sabo has eaten Ace's reborn Flame-Flame Fruit.

There exists a Curséd Fruit Encyclopedia (呪い実図鑑, Noroi Mi Zukan) that lists the names and abilities of all the Curséd Fruits. However, only a few of them have illustrations, meaning that most Curséd Fruits cannot be identified by their shape and color. For example, the Gum-Gum Fruit and the Dark-Dark Fruit had pictures and could be recognized prior to consumption, whereas the Bubble-Bubble Fruit and the Ox-Ox Fruit, Model: Giraffe did not, and could only be determined by the abilities they granted.

One individual known to utilize this book is Blackbeard, who, in his search for the Dark-Dark Fruit, memorized its shape from the illustration provided. Sanji also read the Encyclopedia when he was young, and became interested in the Clear-Clear Fruit.

Growth
When a Curséd Fruit user dies, their ability is reborn into another fruit of the same kind. Instead of growing from a plant, the ability simply regenerates inside another existing fruit, as seen when Smiley "died" and the Sala-Sala Fruit, Model: Axolotl transplanted itself into a nearby apple. Another characteristic of a Curséd Fruit's growth is that the stem becomes noticeably curlier than it was when the fruit was not endowed with the ability. In the anime, it was also shown to change its color.

Fruits shown after their possessors' death
Last Possessor: Ace D. Portgaz Status: Eaten by Sabo Last Possessor: Newgate Ward Status: Taken by Teech D. Marshall, using an unknown method. Last Possessor: Smiley Status: On Punk Hazard, currently free.
 * Flame-Flame Fruit
 * Tremor-Tremor Fruit
 * Sala-Sala Fruit, Model: Axolotl

Side Effects of Curséd Fruits
With this new power comes a weakness: the sea rejects the new Curséd Fruit user and they become helpless while submerged in water (or "become a hammer," in Japanese parlance). Though the terminology is usually referring to the inability to swim a more accurate definition is that the sea water itself is the weakness as opposed to the actual motion of the body to move in the sea which simply becomes impossible once one has consumed a Curséd Fruit. Not touching the water itself however will allow the user to go unaffected even if submerged, shown when the Monster Six used diving gear to reach the sunken St. Briss, and again when the Monster six coated themselves in smaller bubbles of Yarukiman Tree Resin bubbles to battle the Kraken. Oda stated in an SBS that Curséd Fruit users are susceptible to all types of water, not just seawater. This includes the white sea surrounding Skypiea. He elaborated on this, saying that "moving" water, like rain or waves, does not weaken Curséd Fruit users, while standing water does. This was also shown first when Luffy D. Monkey was in the Boogie Powder induced rain and did not feel his power slipping away, and again when on Zou, the sea water that Zunesha used to shower did not affect him despite being sea water as it was "moving" water. Furthermore a Curséd Fruit user will not be restricted in the water if he or she is not physically touching the water. Sometimes the power of a Curséd Fruit involves water, or at least some state of water, like the bubble power of Kalifa or the ice power of Kuzan. In that case the user will not be weakened by its own state of water but will still be weak against others states of water.

Oda also said in an SBS that it is not until a Curséd Fruit user is knee deep in water that they become immobilized. This is seen with the Gorgon Sisters and Luffy in Hancock Boa's bath. Brook was also seen slowly losing his strength as the water levels increased in the floods in Ryugu Palace, demonstrating that being in contact with the sea does not instantly rob their strength unless it reaches a certain level.

Even if a part of the user is submerged, they cannot use their Curséd Fruit powers, no matter how much or how little is submerged. However, if the user's body has been permanently altered by the fruit, then the user's ability can be manipulated by outside sources; e.g., when Luffy was knocked into and sunk to the bottom of the pool at Arlong Park, Genzo and Nojiko dove underwater and stretched his neck so his head would be above water, allowing him to respirate. It should also be noted that although all Curséd Fruit users are weak against water, the power itself may still works underwater (for example, Galdino can survive underwater by creating a bowl of wax surrounding him, and the keys he creates can be used to open Sea-Prism Stone handcuffs.) Being weak against the sea proves deadly to many Curséd Fruit users who are pirates and Navy sailing the Grand Line. Additionally, the use of a Curséd Fruit puts users at odds with races like the mermen, and some with greater weakness to the sea than normal (such as the Shadow-Shadow Fruit whose zombies are purified with salt) are almost useless against these races. However, the Curséd Fruit power will also render a Fishfolk or Mermen just as weak in water as it would anyone else, so this advantage is only applied to one that has not consumed a Curséd Fruit themselves.

Sea-Prism Stone, a special substance that emits the same energies of the sea, can also cancel out Curséd Fruit powers through physical contact with the user. How weakened the user's movements become depends on how much physical contact the user has with the Sea-Prism Stone. In addition, all other Curséd Fruit users will have their powers nullified when they are grabbed by the user of the Dark-Dark Fruit.

One rumor, as recounted by Jabra, is that Curséd Fruits house actual devils that will fight when placed in proximity of one another. The resulting battle would destroy the users' bodies. Nevertheless, Blueno contradicted this claim, stating that Grand Line scientists have noted that the phenomenon of one's body destroying itself only occurs when one consumes two Curséd Fruits.

Consequences of Consumption
"Regardless of the type of power, it all depends on how you use it. The chances of you weakening from it are very low. Besides, being a hammer isn't much of an inconvenience."
 * —Lucci Rob on Curséd Fruit power.

The main attraction of eating a Curséd Fruit is the power bestowed upon the user, with many spending their entire lives seeking out just one specific fruit. More often than not, the benefits and uses bestowed by power far outweight the loss of the ability to swim. However, due to lack of information known by most, and with Curséd Fruits that are still unknown, the average consumer plays Russian Roulette when consuming one, without knowing what fruit it may be. With no way of removing the curse, all Curséd Fruits users are labeled as "freaks", "Devils", and "monsters" for the remainder of their lives. All Curséd Fruit users have to be trained to a certain degree, from simple activation control to full combat techniques.

"You could sell 'em for hundreds of millions. But one bite might leave you with a lifetime of problems, you know!?"
 * —Jabra's warning to Kalifa and Kaku.

Another problem with the Curséd Fruits is that a few of them offer "weird" or "useless" powers. While many citizens can be fascinated by their powers, others may leave a consumer leading a miserable life full of discrimination from those around them. However, due to the lack of information within some societies and cultures, misconceptions on how this power was achieved can lead to manipulation of individuals for that user's own purposes.

Artificial Curséd Fruits

 * Main article: Artificial Curséd Fruits

Dr. Vegapunk, a Navy scientist, is heavily responsible for the research into the effects of Curséd Fruits' and Sea-Prism Stone. His research has also led him to devise a method that allows an inanimate object (such as a gun or a sword) gain the effects of a Curséd Fruit (it has not yet been shown how this is done and this has been only done with Zoan types that transform the weapon into an animal). He also managed to replicate the effects of one fruit to a certain degree, and has even created a synthesized Curséd Fruit, though it was said to be flawed.

Caesar Clown stated that he has done numerous experiments on his own Curséd Fruit, insinuating that he managed to enhance its power after consumption. He has not yet explained what his research was or how he did it though. He also managed to create his own version of artificial Curséd Fruits, whereas Vegapunk failed; these are restricted to the Zoan class, named Smile.

Rumble Balls

 * Main article: Rumble Balls

Chopper Tony Tony, during his six year apprenticeship under Dr. Kureha, created a drug called the "Rumble Ball" that enhances the effects of his Curséd Fruit. Thus far he is the only one shown to have consumed it. According to him, the Rumble Ball disrupts the wavelengths of Curséd Fruit forms. It is implied that the "Rumble Ball" will activate when consumed by any Zoan type Curséd Fruit user, albeit with different but slightly similar effects. After two years of training and research, Chopper was able to replicate the Rumble Ball's effect without having to consume any at all (except in the case of his Monster Point, which now requires only one and is under his full control).

Paramythia

 * Main article: Paramythia

The most common of the three classes, Paramythia class Curséd Fruits offer their users superhuman physical abilities or traits, such as shock wave generation and locking onto targets. Other fruits can alter features of the body such as a rubber physique or a body of blades, or the people, objects, and environment around the user, like levitating objects or turning people into toys. Finally, there are some users that can manipulate and generate some kinds of substances, such as wax and poison.

Zoan

 * Main article: Zoan

The users of Zoan class Curséd Fruits gain the ability to transform into an animal (and acquire every trait affiliated with said animal). The user can also transform into a human-animal hybrid form or a twin-beast hybrid. Zoan fruits can also be transferred into weapons, such as guns or swords. There are Zoan Curséd Fruits based not only on common animals, but also on prehistoric animals like dinosaurs and mythological creatures as well (ancient and mythological are rarer than the typical Zoan fruit, with mythological said to be even rarer than Logia Devil Fruits).

There also exist artificially manufactured Zoan Curséd Fruits, fashioned by Vegapunk and Doflamingo Don Quixote. While Vegapunk's fruit was a failure, Doflamingo's fruits, renamed "SMILEs", were a success. They are manufactured in his factories using Caesar Clown's SAD, and sold to big names of the sea. Kaido of the Four Emperors even used them to create an army of Curséd Fruit users.

Logia

 * Main article: Logia

The rarest of the three Curséd Fruit classes, Logia class Curséd Fruits offer their users the ability to transform themselves into an element, whether it be solid elements like ice or sand, liquids like mud or syrup, gases like smoke and poison gas, forms of plasma (in some cases, energies) like fire and lightning, or into a materialization of abstract concepts such as darkness. This can effectively make them intangible, making physical attacks harmlessly go through them, or allow them to be able to absorb the attack completely. They also gain every ability related to that element and gain the skill to disperse, control, and rejoin any part of their bodies while conscious and in control of their powers (including explosions, bullet wounds or cuts). Logia users can move every part of their transformed bodies while in element form.

Unidentified Curséd Fruits
The following is a list of unnamed Curséd Fruits.
 * Kid's unnamed Curséd Fruit, which allows him to manipulate magnetic forces.
 * Bonney's unnamed Curséd Fruit, which allows her to manipulate the age of a person and herself. It is suggested that she can not manipulate the age of inanimate objects since her victim's clothing does not change.
 * Hawkins' unnamed Curséd Fruit, which allows him to create straw voodoo dolls and use them to redirect physical damage from his own body. Damage incurred by the dolls will be exhibited by those whom the doll represents. Hawkins can also transform into a straw-man. Kizaru stated that it is not a Logia.
 * Apoo's unnamed Curséd Fruit which allows him to morph body parts into instruments and use music as a weapon.
 * X Drake's unnamed Curséd Fruit, an Ancient Zoan which allows him to take the form of a dinosaur.
 * Urouge's unnamed Curséd Fruit, which allows him to convert damage taken into strength, expanding muscles.
 * The unnamed Curséd Fruit eaten by an unknown prisoner from Impel Down. It gave this person the ability to tunnel, and was used to create the secret floor between Level 5 and Level 6 of Impel Down, Level 5.5.
 * Minotaurus' unnamed Curséd Fruit, an Awakened Zoan which allows him to take the form of a cow.
 * Minokoala's unnamed Curséd Fruit, an Awakened Zoan which allows him to take the form of a koala.
 * Minozebra's unnamed Curséd Fruit, an Awakened Zoan which allows him to take the form of a zebra.
 * Minorhinoceros' unnamed Curséd Fruit, an Awakened Zoan which allows him to take the form of a rhinoceros.
 * Minochihuahua's unnamed Curséd Fruit, an Awakened Zoan which allows him to take the form of a chihuahua.
 * Raffit's unnamed disputable Curséd Fruit, which allows him to form wings for flight.
 * 's unnamed Curséd Fruit, which allows him to turn into diamond.
 * 's unnamed Curséd Fruit, a Mythical Zoan which allows him to transform into a phoenix.
 * 's unnamed Curséd Fruit which lets him keep things such as a giant hammer in a pocket that is in his body.
 * 's unnamed Curséd Fruit that lets him sprout spider-like arms from his back as well as grow a spider's abdomen.
 * 's unnamed Zoan Curséd Fruit which allows him to turn into a dalmatian.
 * 's unnamed Curséd type Devil Fruit, which allows him to take the form of a caterpillar.
 * Kin'emon's unnamed Curséd Fruit which transforms small items placed on a person's head into something that can be used as a disguise (based on the user's imagination and memory) which lasts until removed. Kin'emon says it relates to sorcery.
 * Issho'sunnamed Curséd Fruit that gives him the ability to manipulate gravity.
 * Kanjuro's unnamed Curséd Fruit that allows him to bring whatever he draws to life. Like Kin'emon, he refers to it as sorcery.
 * Sheepshead's unnamed Curséd Fruit that allows him to transform his hands into the horns of a sheep.

Unnamed Artifical Curséd Fruits

 * Momonosuke's unnamed artificial Zoan Curséd Fruit, which allows him to transform into an eastern dragon. It was artificially created by Vegapunk, and was said to be a failure.

Unnamed Non-Canon Curséd Fruits

 * Chiqicheetah's unnamed Curséd Fruit that allows him to turn into a cheetah.
 * Alpacacino's unnamed Curséd Fruit which gave him life and the ability to transform into an alpaca.

Curséd Fruits of Undetermined Class

 * Smash's Plasma-Plasma Fruit, which allows him to generate and manipulate plasma. It is currently not known whether this fruit is a Paramecia or Logia.
 * Tesoro's Gold-Gold Fruit, which gives him gold-related abilities.

Named Curséd Fruit Count

 * Paramythia: 51* (Canon), 19 (Non-Canon), 2 (SBS)
 * Zoan: 18** (Canon), 3 (Non-Canon), 0 (SBS)
 * Logia: 11 (Canon), 3 (Non-Canon), 0 (SBS)
 * Unspecified: 0 (Canon), 2 (Non-Canon), 0 (SBS)
 * Total: 80* (Canon), 27 (Non-Canon), 2 (SBS)


 * ''* Note: These numbers include the Float-Float Fruit, which was not named or detailed in the manga. It is deemed to be a canon fruit because Shiki's escape from Impel Down (which involved the fruit) was mentioned in the manga.
 * ** Note: This number excludes Artificial Curséd Fruits.

Early One Piece
In the original two pilots of One Piece, Luffy's Curséd Fruit power, the Gum-Gum Fruit, was the power of the Gum-Gumtree that grew once every 50 years and there were no signs that other such powers existed.

Translation and Dub Issues
Many of the fruit names come from Japanese onomatopoeia and Japanese vocabulary. In some cases finding a suitable dub or translation name is awkward.

Manga and Anime Influences
The rumor that Jabra recounted about Curséd Fruits housing actual devils is similar to the Hindu belief about belerics; because of this the Hindus of Northern India avoids the trees and will not sit in its shade. However, Beleric fruit is also known for its medicinal properties and is used by Hindu physicians for various ailments.

The other part of Jabra's rumor about the fruit's devil tearing out and killing the consumer from within is similar to another Hindu legend, particularly the version in Villivakkam, about two asura brothers: Vatapi would take the shape of a fruit or meat and Ilvala would offer the "food" to innocent mendicants passing by. Vatapi would come out by tearing through the victim's body. However, this failed against Agastya.

Trivia

 * According to Pell, there are five known types of abilities that allow the users to take flight. In the series, more than five Curséd Fruits that grant the ability of flight have been seen. The exact number is debatable, and even more so since Spandam claimed that there are Curséd Fruits that have yet to be cataloged, and therefore unknown.
 * Teech D. Marshall is the first person shown to assimilate a Curséd Fruit power from a corpse of another Curséd Fruit user. He is also the only person to have two Curséd Fruit powers at the same time, and is currently adding more to his arsenal.
 * In an SBS question, a reader asked if he could get Luffy's Gum-Gum Fruit powers by eating Luffy. Oda answered no, and that he would get food poisoning instead.
 * Whenever a filler Curséd Fruit is going to be used in a filler arc, the writers ask permission to use it from one of the authors, Oda. In a SBS Oda described the process as "Basically, all that happens is that the anime's scriptwriters come up with powers that they want to use in the story, and I say 'Yeah, that sounds good', or 'No, sorry, I want to use that one in the future'. That's all."
 * Certain Curséd Fruits are noted to be unique or special, even for their respective classes. Such include the:
 * Rumble-Rumble Fruit, which has been deemed as one of the few "invincible" Curséd Fruits.
 * Dark-Dark Fruit, which has been claimed to be "unique", even for a Logia.
 * Tremor-Tremor Fruit, which has been called the strongest Paramythia, equal to a Logia.
 * Op-Op Fruit, which has been called the "Ultimate Curséd Fruit".
 * Currently, only two (canon) Curséd Fruit users have a Laughter Style based on their respective Devil Fruits; Perona, the user of the Hollow-Hollow Fruit (Horohorohoro). The non-canonical villain, Breed, the user of the Pet-Pet Fruit, also shares this trait (Petototo).
 * In the real world (in english), "Logia" is plural for Logion which is a saying attributed to Jesus Christ and "Zoan" which is a biblical name for Tanis. And "Paramecia" is plural for Paramecium which a single-celled fresh water animal.