Shaun White is under fire from special needs parents AND the Special Olympics over his Halloween costume -- "Simple Jack" from "Tropic Thunder."
Remember, when the movie came out back in 2008, several disabilities groups blasted Ben Stiller and the flick for the character -- an intellectually disabled man who is repeatedly referred to as the r-word.
Now, 10 years later ... White thought it would be a good idea to trot out the costume for a Halloween party and people are pissed.