Goblin artillery

At the beggining of each turn, choose a number.
It cannot be more than the number of Mountains you control.
At the end of any player's upkeep, choose a creature at random. Goblin artillery deals 3 damage to that creature. Repeat this process X times, where X is the number you have chosen at the beginning of the turn. A creature can be damaged multiple times that way.
Binoculars aren't very popular among Goblins.