Registeel

Slow Start 1
Cold Heart 3 - When this creature dies, you may sacrifice any combination of three artifacts and/or creatures. If you do, return it to the battlefield.
{c}{c}{c}{c}{c}{c},{t}: Registeel gains your choice of hexproof or indestructible.
{1}{c}{c},{e}{e}{e},{ut}: Destroy each artifact target player controls. If three or more artifacts are destroyed this way, you lose 4 life.