A gifted Federation engineer and one of the designers of the Enterprise's engines, whose unrequited love for Miranda Jones leads him to attack the Medusan ambassador Kollos and lose his mind.
Larry Marvick is a Federation engineer who helped design the engines of the Constitution-class Enterprise. He appears in the third-season Original Series episode Is There in Truth No Beauty?, where he was played by David Frankham.
Marvick comes aboard with the telepath Miranda Jones and the Medusan ambassador Kollos, with whom he has been working on applying Medusan navigation to starships. He is in love with Jones and resents her decision to devote her life to Kollos. When she rejects him he tries to kill the ambassador, but catches sight of the Medusan without a protective visor and is driven mad.
In his frenzy he seizes engineering and hurls the ship at enormous speed out of the galaxy into an uncharted void. He dies shortly afterwards, still raving, leaving Spock to mind-link with Kollos to steer the ship home.