Killer Klown from Outer Space

First appearance: Killer Klowns from Outer Space (1988)

Late one night a strange circus tent shaped spaceship lands on the outskirts of town. The occupants proceed to harvest the people of the town. It's up to two horny teens, their best pal, his girlfriend and their buddy in the police force to save the day! You won't look at cotton candy or popcorn the same again.

Much more terrifying clowns than Pennywise could ever hope to be!

Features a fantastic theme song by the Dickies

The video for the theme song:

Regan McNeil / Captain Howdy / Pazuzu

First appearance: The Exorcist (1973)

A young girl gets a little to close to her imaginary friend making her actress mom's life miserable. Fortunately there's an old priest and a young priest that know what to do about it. 

Crite

First appearance: Critters (1986)

Small ravenous alien criminal carnivores steal a spaceship and crash in a small rural american town making life miserable for the family they land near. Luckily bounty hunters UGG and LEE are on the case! The town drunk gets a new lease on life.

One of the better "little monster" movies to come out in the "let's make another Gremilns" era of filmmaking. Spawned 3 sequels (two more than Gremlins) and started the tradition of "We've got to set one chapter of our franchise in space" usually Part 4.