(Razorverge Scrub isn't a spell.)
When Razorverge Scrub enters the battlefield, sacrifice it unless you pay 1 life.
All creatures have Mountainwalk.
: Add or to your mana pool.
Sacrifice Razorverge Scrub: Add or to your mana pool.
: Add 
or 
to your mana pool. or to your mana pool.
