The False Hydra

Deathtouch, first strike, lifelink

Whenever a creature dealt damage by the False
Hydra dies, put a +1/+1 counter on it.

Pay 5 life, remove five +1/+1 counters from the
False Hydra: It phases out. (Until your next
upkeep, it's treated as though it doesn't exist.)

"Perhaps it is still there, the black rot at the center.
But how do we know?"