Murhan Colossus

Mountainwalk, Haste
{t}: add {r}{r}{r} to your mana pool.
As long Murhan Colossus is under your control,
all your mountains become Land Creature
Dragon 3/3 with Flying.
Whenever this creature attacks, you can sacrifice
one Dragon creature for deal 3 damage at a target
card or opponent, or add the type mountain to
a target land's types.