2. Horta

From: ‘The Devil In The Dark’ (Star Trek, Season One)

What is it? A native of Janus VI, this rocky, silicon-based being uses corrosive acid to slice its way through the walls.

Quite how it manages to sneak up on people to kill, them, however, is anyone’s guess.

Cheesy or cool? Both. The costume itself is distinctly fromage-feeling, given that it appears to be a rug with some plastic lava chunks stuck to it.

But the creature itself is revealed as a fully rounded creation, a mother desperately trying to protect her children, and discovered when Spock mind melds with it. “No Kill I” indeed!

Fact me ‘till I fart: The creature was similar to one from an Outer Limits episode called The Probe. Janos Prohaska was the man under the carpet costume for both shows.