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Clockwork Hydra enters the battlefield with four +1/+1 counters on it.
Whenever Clockwork Hydra attacks or blocks, remove a +1/+1 counter from it. If you do, Clockwork Hydra deals 1 damage to any target.
{T}: Put a +1/+1 counter on Clockwork Hydra.
If Clockwork Hydra leaves the battlefield while its trigger is on the stack, you can’t remove a +1/+1 counter from it, so it won’t deal damage.
If the chosen target is an illegal target by the time Clockwork Hydra’s triggered ability tries to resolve, the ability doesn’t resolve. You don’t remove a counter from Clockwork Hydra.
