5. Ceti Eels

From: Star Trek II: The Wrath Of Khan

What is it? Small, squiggly, slimy monstoids that look like a cross between a beetle and a lobster. They crawl in through the ear, wrap themselves around the cerebral cortex and set up home, making the victim susceptible to persuasion.

Oh, and causing sheer agony.

They were used by Khan Noonien Singh to control Chekov and Captain Terrell so that he could trick Kirk.

Cheesy or cool? Cool. The freakish little beasties suffered from a few shots that made them look cheaply made, but director Nicholas Meyer handled them brilliantly.

Just don’t watch it you have a phobia of anything getting in your ear…

Fact me ‘till I fart: The name “Ceti Eel” doesn’t actually appear anywhere in the film. Khan never names ‘em and Kirk doesn’t recognise the creepy crawlies.