You could try drilling the snot out of it till it breaks apart and retrieve the pieces in the pump basket. That is if you have a 18" bit and the dexterity not to drill a hole into the side of your pipe.

Here's a thought, what if you disconnected your skimmer intake to the pump and put that on the output part of your pump, keeping your main drain as the source of intake to the pump... maybe you can blow it back out the way it came. Just make sure no one is looking down the skimmer basket when you turn it on.