In southern arizona they have the sorts of cacti that have great arms like you see on old westerns, called saguaros. they're quite protected by various laws and live to be hundreds of years old.
In 1982, roommates David Grundman and James Joseph Suchochi decided pack up the guns and go wandering in the desert two miles north of Arizona 74, just west of Lake Pleasant. One or both of them was struck with the brilliant notion of taking pot shots at saguaro they found growing there. Maybe it was the Devil in them. Maybe it had to do with the eerily manlike shapes these monstrous plants can grow into.
Grundman shot a small saguaro in the trunk so many times that it thudded to the ground. "The first one was easy!" he cried, according to Suchochi. He next chose a specimen which stood 26 feet high and was estimated to be a hundred years old. Before the ringing in his ears had stopped, a four-foot spiny arm, severed by the blast, fell on Grundman, crushing him.
Quite scary, huh? That is blood-less horror. It's the horror that lives in us. Plus, that very story reminds us that plants – though being constant and still – can still attack back.