3, Tap: Reveal cards from the top of your library until you reveal a land card. Goblin Charbelcher deals damage equal to the number of nonland cards revealed this way to target creature or player. If the revealed land card was a Mountain, Goblin Charbelcher deals double that damage instead. Put the revealed cards on the bottom of your library in any order.
Without any lands, you will keep revealing cards until you can't anymore or until you reveal a land card. Once you stop revealing, then you deal damage.