M. Night Shyamalan ain't got nothing on this twist!
...Okay, maybe he does, but I'm betting this will surprise at least a couple people anyway. Truth is, though, Susan's objections to the cow form are fairly limited, and her main issue with it was already explained (at least somewhat) to her satisfaction.
Incidentally, in spite of the "playtesting" joke in panel two, I totally think swap should work this way and keep cumulative effects going instead of resetting them.