{2}, {T}, Sacrifice Horizon Spellbomb: Search your library for a basic land card, reveal it, put it into your hand, then shuffle. When Horizon Spellbomb is put into a graveyard from the battlefield, you may pay {G}. If you do, draw a card.
2013-04-15
When you sacrifice Horizon Spellbomb, it's search ability goes on the stack, and then the triggered draw ability goes on the stack on top of it. This means you first choose whether to pay {G} and draw a card, then you search; you do not search first.