Mjolnir's Might

Tap {r}{r}, during your upkeep or bury Mjolnir's
Might
{r}{r}{r}, Mjolnir's might does 2 damage to target opponent and each creature target opponent
controls. If more than {r}{r}{r} mana is spent in
this way, exile Mjolnir's Might at end of turn.
"Take mine and end this!"
— Thor god of Thunder