After some research, found the answer. It turns out the eyeball return has a male-male threaded piece that screws into the standard 1 1/2 inch pipe, but has a NONstandard thread that extends into the pool. (Why do they do things like this????) There is a special tool to remove this piece, that costs about 11 bucks. I have ordered the tool, and then should have a nice standard pipe to connect to.

EricF