(Goblin Flats isn't a spell.)
Whenever Goblin Flats becomes tapped, it deals 1 damage to you.
, : Tap target artifact with converted mana cost X or less.
: Add or to your mana pool.
: Add to your mana pool. Put Goblin Flats on top of your library.
, 
: Tap target artifact with converted mana cost X or less.: Add 
or 
to your mana pool.: Add 
to your mana pool. Put Goblin Flats on top of your library.
