This was one of the better episodes in the final season of Star Trek the Next Generation. The plot involves Reginald Barclay who complains about coming down with an alien fever. He is treated by Dr. Crusher who injects him with a serum to activate a gene that would help him to feel better. Unfortunately, the treatment results in a ship wide gene mutation to everyone on board. Picard and Data have gone on a shuttle craft mission prior to the infection and return to find the ship adrift in space. Everyone on board has mutated backwards on the evolutionary scale (Deanna to an amphibian, Barclay to a spider, Riker to a early form of hominid, Worf to a reptile form, Nurse Ogawa to a early ape, and Spot to an "iguana"). By coming on board, Picard also becomes infected and begins to act like an early ape. Data gets crucial information from the birth of Spot's kittens and uses the embryo of Nurse Ogawa to help to revert the mutations.
