The never-broadcast Fear Factor stunt involving donkey semen and urine did air, but on Danish television–and, thanks to someone videotaping the screen, on YouTube.
It’s actually very tame and significantly less gross than most of the gross-eating stunts the show has done, because ultimately it’s just people drinking out of mugs; NBC replaced this episode with one featuring contestants eating and barfing insect smoothies.
One of the pairs featured on the show were threatened by NBC after discussing it in detail on a radio show. Claire Odioso said that she “vomited it my glass and just drank that” and said “everyone was throwing up,” including camera operators. But that’s not at all apparent in the edited version.