Ensign Garrovick is a young Enterprise security officer in Obsession, the son of Kirk's late commander on the Farragut, who blames himself for hesitating before firing on the vampire cloud creature.
Ensign Garrovick is a newly assigned security officer on the USS Enterprise in the Original Series episode Obsession. His father commanded the USS Farragut and died, with half his crew, when a gaseous creature attacked the ship eleven years earlier, an attack the young Lieutenant Kirk believed he might have stopped.
On Argus X the creature appears again. Garrovick, leading a security detail, freezes for a moment before firing, and men die. Kirk, seeing his own old failure repeated, relieves him and confines him to quarters.
The creature later enters the ship through a vent in Garrovick's cabin, and Spock shows that phasers could never have harmed it. Freed of guilt, Garrovick goes with Kirk to Tycho IV, where the two bait a trap with blood plasma and destroy the creature with an antimatter bomb.