Someone help me find this movie!!!

I know this is unrelated to "The Pit", but it would have been a movie made around the same time. All I can recall is it took place in the woods and there was a log cabin-type house. The main character was a man, and one scene shows the man in the middle of a lake and then this weird white or gray human-like creature pops out of the water and starts to pull him down while he is screaming. Sound familiar to anyone?? Thanks! BTW-I'm posting this on several other older movie message boards, just in case you see it again.