Dr. Ritter

Dr. Ritter is the main antagonist in the fifty-eighth Goosebumps book, Deep Trouble II, as well as its television adaptation.

Deep Trouble II
One year after Billy and Sheena Deep's adventure in Deep Trouble, they are once again on board The Cassandra with their uncle, Dr. D. However this year, they begin to notice something strange going on with the local marine life. Tiny fish like minnows and goldfish are now gigantic. Soon the Deeps are visited by a scientist named Dr. Ritter and his assistants Mel Mason and Adam Brown. Ritter reveals to them that he injected growth hormones into plankton beds to increase the size of fish in an attempt to end world hunger. But now that the Deeps know his secret, they can't be allowed to live. The Deeps are almost thrown overboard, only to be saved by giant seagulls who attack Ritter and his assistants.

The Deeps escape on a lifeboat and wind up stuck on an island filled with giant creatures. They manage to fix their lifeboat and return to The Cassandra. However, they get captured again by Dr. Ritter, who tries to force them into drinking his mutated plankton. He tells them that if a human ingests it, they'll turn into a fish. Billy drinks a vial, but nothing happens, as he actually drank iced tea instead. Before the Deeps can stop him, Dr. Ritter escapes into the ocean and drinks the plankton, turning into a fish and swimming away.

Deep Trouble Episode
In the television adaptation, Dr. Jake Ritter is given a role similar to that of Alexander DuBrow from the first Deep Trouble book as Dr. Deep's lab assistant. Unlike Deep Trouble II, it was Dr. Deep who had created the growth hormone which he named D13. He had used the hormone on the plankton, causing the local marine life to grow gigantic in hopes to help the world. However, unbeknownst to Dr. Deep, Ritter was experimenting on humans, turning them into half human/half fish mutants. He lures Billy, Sheena and Dr. Deep onto an island to be killed by the mutated humans while he steals D13, planning to get rich. But before he can escape, the mutated humans capture him and experiment on him. Dr. Deep uses an antidote to restore the mutated humans, but Ritter winds up as a sideshow freak for the rest of his life.

Trivia

 * The book never reveals Dr. Ritter's first name, but in the episode, it is revealed to be Jake.