Molten Wart-Hopper

Whenever Molten Wart-Hopper attacks, put a lava drop counter on target land defending player controls. (Whenever a land with a lava drop counter is tapped for mana, its controller removes a lava drop counter from it and loses 1 life.)
"I don't care if it has a name; 'Sir Hoppy III' has set fire to half the camp and I want him gone by morning!"
-Goblin Scout Leader