 He attempts to get Dean and Castiel killed when he tells them that they need to summon and kill ancient warriors Gog and Magog and retrieve their hearts as ingredients for the spell.Castiel, realizing there is no other way to safely know the true ingredients for the spell, forcibly extracts the spell from Donatello's mind, leaving him brain-dead and on life support.Sam and Dean are uncomfortable with Castiel's actions, but he tells them that there was no other way.