Would there be any objection to making its ability cost
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? It kinda goes with the delay mechanic. It would also keep the squid and nymph special in that they're mono/mono cost delayers.
Alternatively:
-Make the warden rare
-Make freeze stack, perhaps in a non-linear fashion (e.g. congeal freezes for 4 turns, but every freeze or congeal thereafter only adds an aditional 1 turn)
-Make delay a toggle. If a creature is delayed, hitting it with the warden's ability doesn't add more delay counters, it removes existing ones.
-Make airborne creatures flat out untargettable to the warden
-remove the damage to target mechanic. It's convoluted; save it for something else and keep this as a cheap defensive card.