The chief processing engineer at the pergium mining colony on Janus VI, who in 2267 is the first to fire on the Horta and later leads the miners out to kill it.
Ed Appel appears in the first-season episode The Devil in the Dark. Some fifty men have died in the tunnels by the time the Enterprise arrives, and Appel is one of the few to have seen the creature and lived. He tells Kirk that he hit it squarely with his phaser and it made no difference.
He is sceptical that the Starfleet men can do better, and impatient with the delay when the colony's main circulating pump is stolen.
When the wounded Horta is cornered, Appel heads the crowd of miners who overpower the guards and arrive with clubs. Kirk stops them and explains that the silicon nodules they have been smashing were the creature's eggs. Appel accepts the bargain that follows. He was played by Barry Russo.