Trolls (not the dolls) are ugly and shrivelly, yet strong and long-lived creatures that travel in clans at night and live in caves by day. They can't be caught in the sun, or they will evaporate and die. In their night parties, they will kill people using clubs and daggers, steal food and money, and eat peoples animals and flesh. Great guys, aren't they? If that isn't bad enough, they have another worse crime. They sneak into peoples houses, steal their babies, and train them into slavery. They leave one of their own in the crib, so when the parents come, they see a ideous creature instead of their kid. they then kill the parents and use their homing skills to rejoin their clan the next night. Honestly, I don't think my parents would miss me that much.