Dr. N. Zyme is a character appearing in SWAT Kats: The Radical Squadron. He was voiced by Paul Eiding.
A gentle-hearted biochemist who worked at Megakat Biochemical Labs, Zyme was the primary developer of an experimental compound called Viper Mutagen 268, developed with the assistance of his less than trustworthy colleague Dr. Elrod Purvis. The formula contained snake DNA, due to Zyme's belief that because snakes grew back their tails, Viper Mutagen could stimulate rapid regeneration in plantlife, ending world hunger and deforestation by regrowing destroyed crops and burned down forests.
A greedy Purvis, however, attempted to steal the mutagen, and was caught in the act by Zyme. He chased Purvis to a stairwell, where Purvis punched him in the face. Zyme kicked his briefcase at Purvis, knocking him down the stairs and making him spill the Viper Mutagen all over himself. Although Purvis seemed to die, he actually was mutated into a monstrous part cat, part snake mutant, naming himself Dr. Viper, and attempted to turn Zyme, Callie Briggs and Mayor Manx into mutants as well, only to be stopped by the SWAT Kats.
Some time later, Zyme assisted the Enforcers against Dr. Viper's giant bacteria monsters. He provided Commander Feral with a dose of powerful antibiotics in a giant syringe, but the monsters proved immune. Standing by the lab window with Callie when this occurred, Zyme was distracted by the entrance of his former colleague as Viper called him a fool and bragged about his creatures' immunity to antibiotics. Suddenly one of the monsters smashed through the window and reached its huge, gooey hand down over a terrified Zyme, who screamed. He was never seen again and most likely eaten by the monster offscreen.
Although never explicitly stated, it is strongly implied Zyme dies, making him the only character in the show to appear more than once who gets killed.