|Game(s)||Trap series, Nitrome Must Die|
Boulder trap buttons in the Trap series have a white circle as the icon for the button. Although boulder traps have brick buttons, they use more of the usual wooden buttons for their traps. Boulders released by boulder traps are made up of tan coloured stones in the form of a sphere.
Nitrome Must Die
Boulder traps have a very similar in appearance in Nitrome Must Die, with the only difference being that the colour changed from tan to grey.
When a boulder trap is activated, a boulder from either the left edge or right edge of the screen will roll on. Unlike other traps, boulders have the same appearance no matter what side they come out of.
Boulders will roll either left to right, and come out the left side of the screen when they enter the right, and vice verse. To avoid a boulder trap, the player can either jump up onto the above platform (if there is one) or run through one of the sides of the screen and appear behind the boulder, then jump up to the above platform.
When a boulder touches the player, their character will become flattened, and float back and forth to the ground, instantly being killed. In further levels of Knight Trap, platforms with boulder traps also have other Traps like spikes to make the level harder. Boulder traps appear many times throughout Knight Trap, but a few times in Office Trap.
Nitrome Must Die
Boulder traps are spawned out of pipes and roll down platforms, creating cracks in them. They take a medium sized chunk of health off the player if a collision is made. They appear rarely, and do not hurt enemies.
- In some levels, a boulder may move in the same direction as the boulder above/below it. Boulders may also move opposite of the boulder above or below it in a zigzag pattern.