Endless Prairies of War

Endless Prairies of War enters the battlefield
tapped.
Whenever a player attacks with three or more creatures, that player gains control of Endless Prairies of War.
{t}: Add {r} or {w}. Endless Prairies of War deals 1 damage to you.
{t}: After this phase, there is an additional
combat phase. Activate this ability only once
each turn and only during combat.