Nyra, Wold Bending Madness

Haste, menace
When this creature attacks choose any number of
lands you control. For each land chosen you may
pay {g} then until end of turn it becomes a 3/3
creature with Haste and Menace that's attacking,
it's still a land. For each {g} not paid this way you
lose 2 life and sacrifice a nontoken permanent.
"Oh hi Mr. Wall! Wanna have a race?"