Maro

Maro's power and toughness are each equal to the number of cards in your hand.

Secret Lair Drop

The List

Ninth Edition

Creatures are only put into a graveyard for having 0 toughness when state-based actions are checked. If Maro’s toughness goes to 0 during the announcement or resolution of a spell or ability and then goes back up above 0 before the end of that announcement or resolution, it won’t be put into your graveyard when state-based actions are checked.