The vagina-faced monster that has plagued both Arnie in jungles and Danny Glover in cities and Adrian Brody in a different jungle was a triumph of cool effects, which nobody was really expecting - the production of the original Predator was a total mess, with the alien's design being changed multiple times during filming, and the creature being recast from one chimpanzee (Jean Claude Van Damme) to another (an actual chimpanzee). One weirdly effective little effect that worked from the off was the glowing green Predator blood - made with equal parts KY Jelly and goo from inside a glowstick. SO effective, it's been used in every Predator appearance since.
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/
