Means the same thing as:
Whats up? Whats going down? Whats happening?, Whats doing?, Whats the go? or Whats the deal?
Answer is 'not much' or 'im just doing...' NOT 'good', 'pretty bad' etc.
Variation of 'whats cracking?'.
"Yo' whatz crackulatin', nigga?"
"Nothin', jus' chillin'."
What is going on?