Mutagen

Mutagen is a mucilaginous, radioactive substance that has served as a key plot device in series. 
Any creature that is exposed to mutagen will be affected in a myriad of ways, from growing in size and intellectual capacity, merging with inorganic materials such as metal, or gaining superpowers such as telepathy or telekinesis. 
It is responsible for mutating, among others, Splinter, the four Turtles, and villains such as Mutagen Man or The Rat King.
== Appearance ==
The Mutagen is a cyan, glowing chemical substance.
== Effects ==
The contact with mutagen causes one to merge with the DNA of the last creature one came in contact with. 
If one has not recently came in contact with any living being it causes one to mutate into an undefined blob, as seen with Timothy.
It is shown that when exposed to inorganic matter such as cement, it causes it to dissolve like an acid. 
Considering Timothy stated that mutagen burned him, mutagen in its base form might just be an acid.
The Mutagen is shown to fuse anything that is either metal or high tech to the mutated character's body.
Examples include Cockroach Terminator, Bebop, and Rocksteady.
If ingested, the mutagen causes one to mutate into the last thing ingested before the mutagen. 
For example, Antonio mutated into Pizza Face as pizza was the last thing he ate; a nameless cat mutated into Ice Cream Kitty, as she ingested a mix of mutagen and Ice cream. 
The only known exception are the Squirrelanoids, whose consumption of mutagen simply made them monstrous.
Oddly, the mutagen causes some subjects to lose their intellect in some rare cases.
For example, Dr. Tyler Rockwell and Dr. Kirby O'Neil who became the instinctive beasts "Monkey Brains" and "Kirby Bat", respectively.
* Exceptions:
** Although other intellectuals such like Baxter Stockman and Dr. Victor Falco did not develop a "beast mode", they did develop higher levels of antisocial behavior and psychosis.
In some rare occasions when an animal hasn't recently come in contact with a human, the exposure to mutagen causes is to develop a human level intellect as well as an anthropomorphic mutation. 
One example would be the The Punk Frogs.
The effects of fusion are similar to the regular exposure. 
The main difference is that, as the name implies, fusion merges two or more living creatures instead of just mutating one based on others DNA.
For Example, Mega Shredder and Creepweed.
* It can also cause the merging of organic with inorganic matter. For example, "Cockroach Terminator", which is the fusion of a cockroach and spy equipment.
== Skills & Abilities ==
When touched, it can mutate anything that's alive, Human, Animal and plant.
The Utroms were able to use the Mutagen as a power source for their transmat.
== Users/Owners ==
* The Kraang
* The Utroms
* Eric Sacks