Very simple thing: I'd like the gold token to float while the player is in an encounter that affects it, being discarded if they screw it up and being attached back to the card if they don't (they won't actually claim it until the end of the challenge)

I see "float tokens" for making it float and "land tokens" for putting it back, but how do I discard the token if I want the player to know that they've lost the chance this run?