Name that movie. childrens horror.?

When I was about 6-9 (im 15 now) I remember watching a movie but I cant remember for the life of me what its called, all i remembered was that it was a kids horror and theses kids have like a tree house in the woods and i think the awake some kind of monster and then he comes to eat them or something, and another scene that i remember was that one of the girls of the kids was scared in her bed so she looked under it and nothing was there but when she got up and turned around the monster was in her bed, and monster looked like a little troll...... please tell me if you know that film, i remember i loved that film.