A Florida State football fan wrote a check he couldn't cash ... 'cause he's gone into hiding after promising to eat a steaming pile of dog dookie if his beloved Seminoles lost on Monday -- and now, a ton of big names want to hold him accountable.
An X user by the name @321nole made the eye-popping declaration last week ... stating if FSU fell to Boston College, he would "eat dog s*** out of a red solo cup with a spoon and post a video of me doing it.