(Lake Tomb isn't a spell.)
Lake Tomb enters the battlefield tapped unless you sacrifice a basic land.
, : Tap target artifact with converted mana cost X or less.
: Add to your mana pool. Lake Tomb doesn't untap during your next untap step.
, 
: Tap target artifact with converted mana cost X or less.: Add 
to your mana pool. Lake Tomb doesn't untap during your next untap step.
