Misty Mountains Raider is a uncommon Creature — Goblin Soldier card from The Hobbit (HOB), collector number 105. Current market price: $0.22 (foil $0.26), TCGplayer market prices via Scryfall.
Whenever you attack, amass Goblins 2. (Put two +1/+1 counters on an Army you control. It's also a Goblin. If you don't control an Army, create a 0/0 black Goblin Army creature token first.)