Sandstone Lake enters the battlefield tapped.
: Add or to your mana pool.
Sacrifice Sandstone Lake: Add or to your mana pool.
: Sandstone Lake becomes a 1/1 blue and red Goblin creature with flying until end of turn. It's still a land.
: Add 
or 
to your mana pool. or to your mana pool.
: Sandstone Lake becomes a 1/1 blue and red Goblin creature with flying until end of turn. It's still a land.
