Question: During the go-cart race, several shoppers are sent flying by the errant carts, one of them an old man who yells "Little rascals" at the kids. He's not listed in the credits but I could swear the old man is Robin Williams in makeup.
Answer: That part was originally supposed to be played by Spanky McFarlane, the original little rascal, but died before production began. So an extra was used.
Answer: I tried looking this up on the IMDb and couldn't find anything about Robin Williams there. My only suggestion is to watch it again and see if there is a list of extras in the credits somewhere. Maybe that's all the part was, an extra.