Nether Golem

During your upkeep, pay 2 life or exile Nether
Golem.
{3}: Target instant or sorcery spell you control
with a converted mana cost 3 or less gains Crystallize {3} until end of turn. If that spell is
cast from exile, return Nether Golem to the battlefield under its owner's control at the end
of that player's next turn. You may use this
ability only once a turn and only if Nether
Golem is in the exile zone.