Killer Octopus

When I was a kid, my sister and I watch a movie. I cant remember the title of the movie but I tell you, that movie was awesome. Its not a malay movie and no its not a comedy. It was horror or suspense, I cant decide. I only remember few punchline of the movie. The movie involved a cephalopod or we all call it as octopus or squid whatever. I remember that there were bunch of highschool kiddos and there were murders happen that time. And the highschool kiddos are trying to save their lives from killer octopus. And they uses drugs to keep them safe, yeh I cant remember the function of the drug but then they discover that the octopus was one of them. Yes, the octopus is actually a human that can transfrorm into octopus. I remember that the killer was the sweetest girl from the group and I cannot believe that shes the bad guy. And there are part when they were running from the bad guy or should I say bad girl. My favourite part is in the pool. There is one guy trying to escape the octopus and he ran into a pool. How stupid is that aite? I mean she is an OCTOPUS! She can swim dude! And somehow he manage to escape the pool. Then the girl came out of the pool as well, and she was NAKED! I'm just a kid back then, but I know how hot she was at that time. Her body was hot and shes hot. Okay thats all I remember. I cant remember anything after the naked scene. Anyway, my sister and I wish that we can watch the movie again. We cant remember the title and the actors. If anybody know the movie, please tell me. I mean there was a naked scene, someone must remember. Even I remember, I was just a kid that time and that was my fav part. Hahaha