SWAT Kats Wiki
Dr. Viper
Eye Color: Orange
Hair Color: Black
First Appearance: "The wrath of Dark Kat"
Affiliations: Independent, Katastrophe team (with Dark Kat and The Metallikats)
Occupation(s): Scientist


Vehicle: Via his own plant manipulation
Weapon: Claws
Alias: Dr. Viper
Voice Actor: Frank Welker

Dr. Viper, formerly Dr. Elrod Purvis, is a Kat turned reptilian mutant scientist.


Dr. Purvis once worked at Megakat Biochemical Labs. He tried to steal an experimental regenerative formula he and Dr. N. Zyme were developing. He became covered in the formula when he fell down the stairs and the shock ultimately killed him. The chemicals revived him from death, mutating Purvis into a half-kat, half-snake, half-iguana creature. With expertise in the fields of biology, genetics and robotics, he sought to turn Megakat City into Mutation City and transform the residents into mutants like himself. He was able to turn people like Morbulus into monsters. Dr. Viper is by far the deadliest enemy of the SWAT Kats, and he and his creatures murdered a number of innocent people (including his former colleague Dr. N. Zyme). He first appeared in "The Giant Bacteria." He last appeared in Mutation City. It's possible he returned back to normal since he was at the center of the anti-mutagen blast over the city in his last appearance, or he could have been killed. Voiced by Frank Welker in the original English version.


His reptilian mutation grants him the following abilities:

  • Durable Hide - His reptilian hide has allowed him to survive hits that would kill most kats, such as a multi-story fall and an explosion that destroyed the entire floor of a building.
  • Enhanced Strength - Usually with his tail, he is capable of lifting full grown kats off the ground with it.
  • Blood - His blood is a mutagenic chemical itself, as he fed mosquitos on of his hand, which then mutated in monstrous forms.
  • Regeneration - While it hasn't been shown within the series, he may also have the ability to regenerate, as the formula that mutated him was designed for specifically that purpose.


  • He is similar to the Spider-Man villain The Lizard, though by comparison, He is much more sinister individual as he is primarily motivated by self-interest, the prospect of power and the suffering of others. It is also believed that he was based on DC's Poison Ivy, due to his manipulation of plants and his desire to reduce Megakat City into a mutated swamp.