Zombie Ass: Toilet of the Dead (2011)

Wracked with guilt over the suicide of her sister Ai, who was tormented by high school bullies, pretty young karate student Megu accompanies a group of older friends on a camping trip into the woods: smart girl Aya, her druggie boyfriend Také, big-boobed model Maki, and nerdy Naoi. Things start to go badly when Maki finds a parasitical worm inside a fish they catch – and wolfs it down alive, in the hope that it’ll help keep her skinny! Soon after, and not so unexpectedly in situations like this, zombies show up and begin to complicate things further. After they’re attached by a crowd of poop-covered undead who emerge from an outhouse toilet, the group seeks refuge at the home of strange Dr. Tanaka and his daughter Sachi. But unbeknownst to them, Tanaka has been conducting experiments on the parasites—and the zombies!—and has another fate in mind for the five strangers from the city.