Triffids are giant mutated plant-like monsters that act as the main villains of The Day of the Triffids, in which pockets of humanity struggle to survive in a post-apocalyptic world ruled by these man-eating
plants. Triffids are especially dangerous plants due to the fact they have extremely potent poisonous stingers which they use to kill their prey before they proceed to feast on them: although it is never really explained as to where the Triffids came from the author of the original book has stated that he believed them to be the result of some kind of biological experiment rather than a naturally occuring species or alien invasion. They were later killed by salt water.