Yajuu Yajuu no Mi

The Yajuu Yajuu no Mi (獣獣の果実 Beast Beast Fruit) is a Paramecia type Devil Fruit that grants the user the power to mimic the abilities, senses, and traits, of any animal that the user has come into contact with.

The fruit was eaten by the main protagonist of One Piece:Reach For The Sky, Scott D. Rio.

This ability is not to be confused with a Zoan-class power, as the user cannot transform into an animal they are copying. In the Viz Manga and FUNimation subs, it is called the Animal-Animal Fruit.

This fruit is considered to be extremely rare among most Paramecia devil fruits, as this fruit is the closest fruit to becoming a Zoan user, just missing the ability to transform into the animal they are mimicking.

Appearance
This devil fruit has the standard shape of a typical devil fruit, albeit looking slightly more rounded than the usual ones. It is colored completely purple, and has the infamous Devil Fruit swirls plastered all around its surface.

Interestingly enough, the stem of the devil fruit resembles the tail of a small lizard. Whether this is a foreshadowing that the fruit has something to do with animals or just a common trait among devil fruits is still debatable, but canon is stating that it is more inclined to the latter.

Strengths
The fruit's greatest strength is it's ability to completely and perfectly mimic the ability of any mammal, fish, or mythical creature that the user comes into contact with. To simplify, if the user so much as touches the animal even once, all of it's strength, fighting potential, speech patterns, and knowledge regarding it's species becomes available to the user. However, the user must also concede to the fact that if their will is weaker than the will of the animal they come into contact with, their personality and persona could be overtaken and they could actually become the animal itself, albeit only in personality. This makes the fruit a very dangerous fruit to use for a person who isn't as strong willed as others are.

How the fruit operates is that when the user comes into contact with an animal of any species, that animal's data is sent into the user's brain. From there, all the user has to do is concentrate hard enough and the brain can access that set data of information that the user absorbed and apply it to their body, giving them the athleticism, reflex, and or senses of the animal.

The fruit not only adds the improved senses of the animal, but also factors in the already present abilities of the user, meaning this fruit can essentially double the power of the user, if they are in great physical condition and have above human strength.

Mimicking the animal's abilities does not only just mean gaining their strengths and weaknesses, it also means that the user actually embodies the spirit of that animal and in a sense, becomes that animal but just in human form. For example, if the user were to touch a dog or an eagle, then the user could have access to a dog's heightened sense of smell and an eagle's excellent eye sight. However, as noted earlier, if the user's will is not as strong as the dog's, then the user themselves could be influenced by the dog's personality, and actually think they're a dog.

Another one of the fruit's greatest strengths is the fact that it can replicate any animal, including humans who have turned into animals from their devil fruits. In a nutshell, this fruit potentially has the power to give the user the abilities of any Zoan class devil fruit, albeit if he can touch them long enough to absorb the data.

The level of threat this fruit can very depending on the person who has access to it. On one hand, the user could be as harmless as a kitten, but on the other hand the user could be as dangerous as a dragon.

Weaknesses
The fruit's major weakness lies in the fact that the user has to physically touch the animal for the power to take affect. This makes the fruit useless if the user does not come into contact with any animals during their lifetime. Another huge factor that was mentioned earlier was that, if the user's will or spirit is not as strong as the animal they are mimicking, then their entire persona could be erased, and they could be trapped as whatever animal they're copying forever.

The user can only have access to one fruit at a time and cannot use all of the powers he or she has gathered at the same time, as the overwhelming data would most likely tear the body to shreds.

Also, using the fruit's power too many times can deplete the user's life energy very quickly. Fatigue and exhaustion are two symptoms of a user who has overused the power of the fruit in a day.

Usage
Scott D. Rio, the main protagonist of One Piece: Reach For The Sky ate the Yajuu Yajuu no mi and has access to all of the abilities of any animal he touches. Rio uses the fruit very wisely and uses the powers of the animals he's captured only in situations that calls for them.