transferral potion

[Andrew Hackard]

This is answered (albeit in a slightly different circumstance) in the Munchkin FAQ:

Q. I used an ability to automatically kill a monster. Another player used Wandering Monster to add a monster to the fight, and then played Transferral Potion to move the monster to himself. He beat it. Who gets the level and Treasures for the monster I killed?
A. As of July 2018, if you automatically killed the only monster, combat ended and this whole sequence can't happen. If there were other monsters still fighting, however, this sequence is legal. You get the level and Treasures from the monster you killed after the transferred combat has been resolved. If the other player also wins, you draw Treasures first. (This has been ruled different ways at different times, but we got a ruling directly from Steve, so it is official.)

tl;dr - Only the remaining monster is Transferred. You get the Treasures from the monster you Pollymorphed after the combat is resolved.