(Grass-Wastes isn't a spell.)
Grass-Wastes enters the battlefield tapped.
, : Tap target artifact with converted mana cost X or less.
: Add or to your mana pool. Grass-Wastes deals 2 damage to you.
, 
: Tap target artifact with converted mana cost X or less.: Add 
or 
to your mana pool. Grass-Wastes deals 2 damage to you.
