The Iron Throne of Westeros

When The Iron Throne of Westeros enters the battlefield, gain control of all creatures with converted mana cost X or less until end of turn.
Equipped creature gets +10/+10 and protection from creatures.
Sacrifice three creatures: Destroy equipped
creature. Any player may play this ability during
your upkeep. If they do, exile The Iron Throne Westeros and return it to the battlefield under that player's control.