So it would seem this is a real movie:

The Human Centipede: First Sequence:
Internationally respected Siamese twin surgeon Dr. Josef Heiter has a demented vision for mankind’s future existence. He wants to remove human beings’ kneecaps so they have to exist on all fours and then surgically graft them mouth-to-anus to form a centipede chain. When two stranded female Americans arrive at his luxury home-cum-hospital looking for help, his long-gestating plan swiftly moves into chilling action with a shocking force. Kidnapping a third Japanese male tourist, he begins the tissue matches, teeth removal, and buttock moulding to create his triplet creature.

Oh and why does it say “first sequence”? It’s a proposed trilogy.

It played at Film4 Frightfest and Dread Central has a review.