Forgotten Cave enters the battlefield tapped. : Add to your mana pool. Cycling (, Discard this card: Draw a card.)
Official Rulings for Forgotten Cave
10/1/2008 : Cycling is an activated ability. Effects that interact with activated abilities (such as Stifle or Rings of Brighthearth) will interact with cycling. Effects that interact with spells (such as Remove Soul or Faerie Tauntings) will not.