When Dormant Cavern enters the battlefield, sacrifice it unless you pay 2 life.
: Add or to your mana pool.
Put Dormant Cavern on top of your library: Add to your mana pool.
Cycling (, Discard this card: Draw a card.)
: Add 
or 
to your mana pool.
to your mana pool. 
(, Discard this card: Draw a card.)
