Zinnia, Will of the Vines

{g}{g}{g}{g}: Put a 7/7 green legendary Hydra creature named Overgrowth Hydra with "The legend rule does not apply to this creature" onto the battlefield. It has haste until the end of the turn. Activate this ability only if you do not control a creature named Overgrowth Hydra and only as a sorcery.
As long as you control a creature named Overgrowth Hydra, Zinnia, Will of the Vines has hexproof.