Edward Larkin was a protein specialist on the USS Cabot, serving under Captain Lynne Lucero. He had social and ethical problems, trouble using basic equipment, and was disliked by his fellow crew members.
Larkin was convinced that tribbles could be a food source if genetically engineered to accelerate their reproduction. However, Larkin displayed no understanding of the moral considerations of his project, in particular dismissing questions about the intelligence of tribbles with a suggestion that this could also be engineered out of them. Concerned, Captain Lucero ordered Larkin to abandon his genetic engineering, and transferred him to climatology. Larkin then sent several messages to Starfleet complaining about and insulting Lucero. After Starfleet informed Lucero of this, she decided to transfer him to another starship, over his protests.
His last significant act was to violate Lucero's orders and implement his idea with the tribbles, using his own DNA. Their reproduction was accelerated so much and so quickly that the tribbles could not be contained. After literally filling up sections of the ship, bursting bulkheads, and getting into the ship's circuitry, Captain Lucero ordered the crew to abandon ship. Larkin, however, remained behind, insisting he made a great discovery right up until a wave of tribbles subsumed him, resulting in his death. The Cabot later suffered a complete structural failure, but some tribbles made it to the surface of Pragine 63 and overwhelmed its ecosystem, forcing its civilization to be evacuated. (ST: "The Trouble with Edward")
Edward Larkin was portrayed by H. Jon Benjamin.
Describing his character, Benjamin said, "I think he's perfectly competent as a scientist, just with no moral compass, no perspective, and no social skills. So I think that's where he separates himself from everybody else. That was the big, I assume, comedy conceit of the thing. I think he probably considers himself very good at what he does and that there are no consequences to his research. So he's sort of like a sociopath, I would imagine, but somewhat pathological about his work."