Ice Colossus

If your devotion to white and blue is less han seven, Ice Colossus is a land with, "{t}: Add {4} to your mana pool. If you spend this mana to cast another Colossus, creatures you control gain trample until end of turn."
When Ice Colossus becomes a creature, target opponent sacrifices 3 permanents.
The wall began to tremble, as the very temple we had just journeyed through came to life, and froze half the crew.