Obsidian Caldera enters the battlefield tapped unless you pay .
: Add or to your mana pool.
Put Obsidian Caldera on top of your library: Add to your mana pool.
: Return Obsidian Caldera to its owner's hand.
.
: Add 
or 
to your mana pool.
to your mana pool. : Return Obsidian Caldera to its owner's hand.
