What is a 'scubbawacko?'

My 5 year old called my 2 year old a 'scubbawacko...'
  1. Me: hey, what is a 'scubbawacko?'
  2. 5 year old: I dunno.
  3. Me: You don't know?
  4. 5 year old: It's funny.
  5. Me: ..It's funny?
  6. 5 year old: Because it means something funny.
  7. Me: It sounds funny, but what does it mean to you?
  8. 5 year old: Mom, it just means something IS funny, gosh!
    Ridiculously long eye roll.. One of her best!
  9. Me: Tell me what 'scubbawacko' means!
  10. 5 year old: You're being a 'scubbawacko,' Mom.
    You're right, I am.