Grothmaw, Scadrim Berserker

Doblestrike

Gain {x} manna at the beginning of your turn where
X is the amount of untapped lands your opponents have at the beginning of your turn.
{x}: Grothmaw, Scadrim Berserker gains+1/+1 for each manna tapped, until the end of this turn.
{2}: You may have Grothmaw, Scadrim Berserker fight up to three target creatures of your choice.
{4}{t}: You may have any number of creatures you control fight any number of creatures you don't control.