A drug addict named "Freak" was chased down by Spider-Man after he attempted to steal from the poor at the soup kitchen Spider-Man's Aunt May works at. He stumbles into a laboratory owned by Curt Connors and injected himself with animal gene fluids, thinking they were crystal meth.
Freak then began to form a chrysalis around his body, emerging as a skinless monster. After being shot at by the police, he fell into the sewer and forms another chrysalis. Emerging as an animal hybrid, and completely bulletproof, Freak tracked Spider-Man by his scent after killing a hot-dog seller. After a violent confrontation, Freak gave in to his addictions, and found a meth lab. Spidey followed him, and during the ensuing fight, the building was set ablaze.
Freak was caught under the flaming debris, but survived and created a new chrysalis, which made him fireproof and even stronger. Freak emerged as an armadillo-like creature, and again tried to kill Spider-Man. When Connors arrived with the quicklime necessary to incapacitate Freak, Spider-Man tricked him into thinking Connors had drugs. Freak tore open the bags and was covered in the quicklime. He again formed a chrysalis, with Spider-Man pouring quicklime over it, to permanently incapacitate him. The chrysalis was taken by a hazmat crew, which was later revealed to be an Oscorp research group.
Freak was next seen cut open and hooked up to machines in an Oscorp lab where scientists were using his unique abilities to cure various diseases. Norman Osborn injected him with a sample of the Anti-Venom antibodies to create "super-venom," a virus capable of killing millions with a single drop. He then used the super-venom to re-power Mac Gargan who was "cured" of his symbiote by Anti-Venom. Norman also mentioned that Freak was now incapable of becoming high now because his body adapted to his drug addiction by removing the pleasure center of his brain. In the confrontation between Spider-Man and Osborn, Osborn activated the building's self-destruction, with Freak still inside. A search afterwards by Oscorp found "no signs of life", which made the team reason that Freak was killed, with Osborn immediately retorting "Idiot. Think about it for a second."
Ability to spontaneously come back to life mutated into something capable of surviving whatever danger had killed him, in the form of an accelerated healing factor.
He also has Hulk-like bulletproof durability and strength, acidic saliva, can shoot toxic spores from his body at will, and he can adapt to certain harsh environments.