There's this old movie, it starts with a bunch of kids going out on a camp trip with their advisor. At the end of the movie, you find out the advisor is the son of this crazy woods woman and the movies ends with her getting impailed by this huge log with spikes all over it. Any idea?

Hi would this film be sllepaway camp

Sleepaway Camp (1983) try this link

Might be The Final Terror.

Actually sleepaway camp was the one where the girl angela goes to camp with her cousin and people start dying in really cool ways, anyway it ends revealing that angela is really a boy whose parents died leaving him in the charge of his crazy aunt or something. His aunt already had a son so she made her nephew into a girl and called him angela. Haven't seen the sequels though, maybe it was sleepaway camp 2 or 3.