Thought to become popular in Oakland, CA in the early 70's, the Oakland Octopus is when a man ejaculates inside an anus (producing a jelly baby) and the mass gels inside the rectum. This generally requires about 8-12 hours to congeal and actually forms a "skin" around the feces. When expelled from the sphincter, the fecal matter usually resembles an octopus, complete with tentacles.
OKAY ROOMMATES, LISTEN UP! Everyone is to flush the toilet after taking a dump, NO EXCEPTIONS! Nathan left an Oakland Octopus in the toilet so large that the Discovery channel sent a crew to photograph it!