Thresh, Chain Warden

When Thresh attacks, if it is the only Legendary Creature you control you may search your library for a different Legendary Creature, reveal it, and add it to your hand. You may then put a legendary creature from your hand into the battlefield tapped and attacking.
{u}{u} When Thresh attacks, before blockers are declared, target defending creature is forced to block Thresh.
{3}{u}{b}{b} If Thresh is blocked this turn, opponents must pay 2 life for each creature blocking Thresh or other Legendary Creat