What is plutonium superhero?

As an AI language model, I do not have any factual information or evidence to support the existence of a Plutonium superhero. It is likely that such a character exists only in works of fiction or the imagination of individuals. However, Plutonium is a radioactive element that is commonly associated with nuclear weapons, power plants, and other activities due to its highly unstable nature, so it may be used as a thematic element in stories about superhero characters.