[1.0.1] Unkillable critters in arena

[jenx]

In the regular gme, there are often unkillable critters. They do no damage, but you can't kill them. This bug has been reported several times. But when these occur in the arena, they are very annoying, as they remain in the arena round after round. Could we have a routine to clear the arena of critters at each round end?

[aristalis]

The problem with removing them is you could have a character kite to win without beating them. Need to figure why they become immune.