One might make an educated guess of what it is from the title, but it is so much worse. This clip alone can be emotionally scarring; do not view it under any circumstances if you are faint of heart or possess a weak stomach. Once viewed, it cannot be unseen.
For those not in the know it gives proof once and for all why you NEVER go ass to mouth.
Scariest Powerpoint Ever. You know, the one where he explains in graphic detail exactly how he's going to attach each 'segment' from one's mouth to another's anus, making a complete digestive tract?
Jenny sobbing brokenly for her mom and begging Lindsay for help as Heiter is forcefully sedating everyone before surgery. Poop in the mouth is one thing, but that kind of raw despair? That is disturbing.
The Human Centipede 2:
Twelve People going ass to mouth instead of three people.
Martin breaking a man's teeth while making his centipede, Martin wraps barbed wire around his penis and anally rapes a helpless, constricted woman without mercy.
All parts of the second movie are scary and unsettling.