Is a line made famous by Fats Waller in the 1920s. Fats was a Jazz performer mostly known for his renditions of: "Ain't Misbehavin'," and "Honeysuckle Rose."
Fats: "Who dat?"
ECHO: "Who dat?"
Fats: "Who dat say who day when I say who dat?"
An insulting nickname for early US Italian immigrants. They acquired over 50 different nicknames (according to Irving Lewis Allen - 1983), one of which was spic.
Man 1: Look at Tony's hair. It's so greasy!
Man 2 (calling out to Tony): "Hey, Spic, come over here. I need some oil for my salad!"