a phrase made famous by the youtube video "david blaine spoof."
The two gay guys he is showing his "magic" to repeatedly say this after he does something crazy. Used to describe something ridiculous or incomprehensible. Or as a random outburst, fake expletive or exclamation.
"David blaine" : Are you sure you didn't buy a teddy bear?
1st guy: Yes I'm sure I didn't...
Both: What the eff? What the EFF!!