Appears in: Tremors (1990), Tremors II: Aftershocks (1996), Tremors 3: Back to Perfection (2001), Tremors 4: The Legend Begins (2004)
Scariest moment: Showing their strategic brainpower, the Graboids dig a huge ditch in the path of bulldozer, causing the machine to wreck.
Weakness: Explosives made by backwoods yokels.

There's nothing wrong with a little self-analysis. When we put together our list of the 15 best horror-comedies of all time earlier this year, we unfortunately overlooked one very worthy flick: Tremors, the intelligently written, nicely cast romp about extremely large sandworms known as "Graboids." Rumbling underneath the ground and bursting through dirt to finish humans off, they're the sources of plenty of efficient jump scares and tongue-in-cheek action.

Starring a young Kevin Bacon, Tremors is that rare example of a big-time actor's early horror film role being something to take pride in, not frown upon, a la Brad Pitt in the forgettable 1989 slasher flick Cutting Class.