Dr. Catheter is an actual animal biologist and chemistry researcher who worked with animals to find advances for technology and medicine. He works at a labratory called the "Splice O' Life" which is at the skyscraper building "Clamp Centre". He is working on trying to find cures for illnesses such as rabies and the flu. He was planning to dissect (which means kill in order to study and learn about) on Gizmo, one of the main protagonists of the film, who is a cute little mogwai who was defenseless and too weak to escape from Dr. Catheter and his henchmen assistants Lewis and Wally. Gizmo's only chance he had to attempt to run away was when dancing to music, but was captured by Dr. Catheter and put back in the cage. Billy Peltzer managed to rescue Gizmo and tried to make him keep quiet.
Later on, Gremlins were destroying the Clamp Centre building. They were drinking his potions, and became mutated, such as the Vegetable Gremlin, the Bat Gremlin, Mohawk turning into a spider, a gremlin turning into electricity, one gremlin turns into a female (named Greta), another gremlin's face is horribly disfigured by an acid, and most importantly, the Brain Gremlin. The Brain Gremlin later, after drinking a potion that made him turn from a primitive monster into a highly intelligent creature whose levels of intelligence matched the maximum values of a human being, explains to Dr. Catheter about his own monster species.
The Brain Gremlin then injected genetic sunblock into a gremlin who turned into a gremlin and bat hybrid, ordering him to fly out into the daylight and tell the other monsters when they are able to come out. Dr. Catheter ordered his assistants to catch the Bat Gremlin, but fail and it escapes. Dr. Catheter announces, "The horror! The horror! Things!...stuff!", and exclaims to Billy Peltzer that he has developed a fear of animals, yelling, "I swear to god young man, I will NEVER hurt another thing again as long as I live! Some things, are not meant to be dismantled with!!"
He teams up with Billy Peltzer (who rescued Gizmo from him formerly) with another man named Forster. However, a gremlin bites Dr. Catheter on the hand, and after Billy throws it away, the Electrical Gremlin pops out of a lightbulb and electrocutes Dr. Catheter to death.
- His first name is revealed in David Bischoff's novelization, and is a reference to Christopher Lee's frequent costar Peter Cushing.