BB/ Black Bricks are used to fight bosses, which can help you get gold, and skill points.
Go to the skill tab, and you should find a button that says "Fight Boss" with around 5,000 Black Bricks being needed, although it could cost more later.
Black Bricks. Collecting enough of them allows you to fight bosses
I found this on coolmath originally, but it wouldn't work with my ad blocker, so now I'm here. I'm here to stay, cool math version is very laggy.
