Probably the awfulest tasting sausage is andouilette, an infamously stinky sausage made of portions of pig rectum and intestines. It is considered a delicacy in northern France.
I've smelled some stinky sausage that I wouldn't taste but I've never eaten sausage that I didn't like. The blood sausage I see at the German butcher shop haunts me though. They always offer me a sample when I go in there, just for fun.
They are all the wurst tasting, by definition. Blutwurst would by my pick for the WORST tasting. Right up there with black pudding and haggis. Black pudding is so revolting that it's actually a monster in Dungeons & Dragons, and is the principal weapon wielded by practitioners of the secret Lancastrian martial art of ecky thump.
It is choriflan. That is chorizo mixed with flan. Choriflan is from a TV commercial for dish soap that aired 11 years ago. The commercial implied that the dish soap could clean any disgusting mixture of food left on the plate after a meal, such as chorizo and flan. When the commercial was on TV, it was a dare to eat choriflan. My roommates dared me to eat it.