This spell costs {1} less to cast for each Gate you control.
Gate Colossus can't be blocked by creatures with power 2 or less.
Whenever a Gate enters the battlefield under your control, you may put Gate Colossus from your graveyard on top of your library.
Once a creature with power 3 or greater has blocked this creature, changing the power of the blocking creature won't cause this creature to become unblocked.