Gruk, King of the Hydras

Vigilance, Haste, Trample
Gruk Enters the battlefield with X +1+1
counters on it.
When Gruk, King of the Hydras enters the battlefield, search your library for a creature with {x} in its casting cost, put it into your hand, then shuffle your library. The card chosen gains
convoke if it is a hydra.
Other hydras you control have trample and
reach.