Whaaaa
This word is basically the word "what". Except for the fact that it has four "a"'s and no "t".
Whaaaa is a word to show confusion, shock, or just to show that you have no idea to what just happened. The word "Whaaaa" usually has a question mark behind it.
Paul: "I can't believe that just happened! Did you see that?!
Doug: "Whaaaa?"