When nothing at all is apparent or making since. Used in context when you listen to someone talk, but can not remember what they were saying.
Also known as the phase out system. Sounds good in speech and an easy way to tell your listener that you weren't listening to the conversation without making them mad.
Ex 2: Did you hear what that Bitch said? she was twisting her head and yanking her arms, talking like "ducka ducka ducka"!
Ex 3: What the ducka ducka was that?