[MunchkinMan]

The problem is that Friendship Potion is one of those cards that mucks with the entire combat reward, not just one Monster. Which is why I'm saying it is possible to play it, even in the case of only one Monster, where that Monster has been removed with Pollymorph Potion, all under the "reasonable time" rule, which says that if you're about to win a combat (and let's face it, this would count as some kind of victory, so we do consider it), you must give the other players a reasonable amount of time to play cards to stop you. I'll try to see if we can't get a more definitive answer of the one-Monster case, but for now, yes, it can be played even if the only Monster was removed without killing it.