(Caldera Tar Pit isn't a spell.)
Whenever Caldera Tar Pit becomes tapped, it deals 1 damage to you.
, : Tap target artifact with converted mana cost X or less.
: Add to your mana pool. Return Caldera Tar Pit to its owner's hand.
, 
: Tap target artifact with converted mana cost X or less.: Add 
to your mana pool. Return Caldera Tar Pit to its owner's hand.
