Izer's Trench

If Izer's Trench would enter the battlefield, sacrifice an untapped Mountain instead. If you
do, put Izer's Trench onto the battlefield. If you
don't, put it into its owner's graveyard.
Whenever a creature attacks you and you control
Izer's Trench, you may sacrifice a Mountain to
have Izer's Trench do 2 damage to each attacking creature without Flying or Mountainwalk.
{t}: Add {r}.