Beserker

The Enterprise faces a "beserker," a planet-eating machine made by a long-dead alien race

"Doomsday Machine" : my all-time favorite Star Trek episode including the movies which, other than "The Wrath of Kahn," are bunk, and excluding Next Generation and Deep Space 9, which I never got in to.

Episode: TOS 35 - Doomsday Machine
Season 2, Ep. 6
Air date: 10/20/1967
Stardate: 4202.9