Doc Ock, Sinister Scientist is a common Legendary Creature — Human Scientist Villain card from Through the Omenpaths (OM1), collector number 38.
As long as there are eight or more cards in your graveyard, Doc Ock has base power and toughness 8/8. As long as you control another Villain, Doc Ock has hexproof. (He can't be the target of spells or abilities your opponents control.)