There is rumored to be a black hole in La Crosse, Wisconsin, in which it sucks in all of the dads in the city, therefore leaving everybody with no father figure. (Donut Operator reference)
Hey did you hear about The La Crosse Wisconsin Black Hole?
No what's that?
It's a black hole in La Crosse, Wisconsin that sucks in all of the dads that live there leaving everyone without a father figure.
Oh so that's why I don't have a dad...
similar to (and is the very cool version of) the very uncool phrase "and then some."
"A hole in the back" represents something similar to the idea of a bottomless pit, describing that something may be limitlessly awesome, seemingly limitless in number, or someone just got beat up to no extent, etc.