Just now, I was doing my homework, until a caterpillar (or type of worm) fell from the ceiling. I suspected he was on the ceiling and fell, but still wanted to know what type of insect he is, and if he's harmful. He is still a baby, so he is quite small. He was multiple long hairs, but not many, so you can still see what's underneath. He is dark, mostly brown or dark grey, and has legs only at the upper half of his body. He is pretty fat, and is very active at the moment, though it may just be of stress. His tail is a bit pointed, and his legs are quite thin, unlike other caterpillars. Please let me know what insect he is, and if he is possibly harmful.