Gahru, Frozen Primordial

Overrun, indestructible
Whenever a snow land is tapped for mana, it
produces an additional mana of that type.
{s}{s}{s}, {t}: Creatures with power less than the
number of snow lands you control don't untap
during their owner's next untap step.
"Ah, little brother, you've woken, and brought winter
with you." - Aerreon