$monster[piranha plant] should be marked as NOCOPY (or at least it cannot be fought via Back-Up)
> lastCopyableMonster
> [ now: piranha plant, default: ]
[200] The Castle in the Clouds in the Sky (Ground Floor)
Encounter: Renaissance Giant
Round 0: ckb1 loses initiative!
Round 1: ckb1 casts BACK-UP TO YOUR LAST ENEMY!
Round 2: your opponent becomes a Foodie Giant!
> lastCopyableMonster
> [ now: piranha plant, default: ]
[200] The Castle in the Clouds in the Sky (Ground Floor)
Encounter: Renaissance Giant
Round 0: ckb1 loses initiative!
Round 1: ckb1 casts BACK-UP TO YOUR LAST ENEMY!
Round 2: your opponent becomes a Foodie Giant!