The Bloon Hole is a road item that looks like a black hole. You have to place two of them, a red and a blue. When the bloons pass through the red hole, they immediately go to the blue hole. 25 bloons can pass through the hole.
All bloons can pass through the hole, except MOAB-class bloons and the final boss.
This costs $225 because it can stop an entire wave of ceramic bloons!
This road item has a cooldown of 5 min, and you need rank 10 to use it!