Erm.... weird is the word that springs to mind, plus sick.

Some creepy scientist / surgeon guy manages to drug 3 youngsters and carry out an operation that effectively joins them butt to mouth to create his human centipede.
The part where the lead needs to go poop kinda makes for a very sick moment or two and some may even find that bit hard to watch.

A good film to watch if you've nought better to do with 90mins.