Mardu Foundtree

Raid- At the beginning of your
postcombat main phase, add {r}{r},
{w}{w}, {b}{b}, {r}{w}, {w}{b}, or {b}{r} to your
mana pool if you attacked with a creature
this turn.
The tree was a remnant of the Abzan kintree forests, but the Mardu had stolen it and taught it the ways of war.