Boulders are unique placeable 2x2 foreground objects, and are stationary when placed. When unsupported, they fall and begin to roll away. They pick up speed and damage players, 敵怪 and NPCs along their path. Boulders will also begin to roll if mined with a 鎬 or 鑽頭, meaning that they cannot be picked up again once placed.
Boulders will roll across flat surfaces and down slopes, but will break and disappear on contact with an obstacle. On contact with entities, they cause extreme damage in the range of 60-150 per hit. Boulders pierce through an unlimited number of entities.
Boulders always roll left, unless there is no space for them to go left, in which case they roll right.
Boulder traps occur naturally in the 地下 and 洞穴 layers, and consist of a single Boulder in the ceiling, supported by six (2x3) 通電石塊s 電線d to 壓力板s. If a player walks onto the Pressure Plate, the Boulder falls and damages any players or entities it hits.
- Boulders will deal about twice damage in 專家模式.
- Once rolling, Boulders cause the same amount of damage regardless of their speed. A player or enemy hit by a Boulder that just began rolling will take just as much damage as they would from a fast-moving Boulder. This also means that if you try to mine it while touching it, you will be hit.
- Boulders are not supported by 桌子s or Workbenches. Placement on those will work, but the Boulder will fall through immediately, skipping its stationary state. Rolling Boulders that encounter one of these will fall through them.
- Boulders can be placed atop 書架s.
- Boulders can activate red, green and yellow (NPC-sensing) 壓力板s.
- Boulders can be placed on top of each other and will remain stationary. Mining the bottom Boulder causes all of them to fall and roll. Mining only the top Boulder causes only that one to roll off.
- Boulders are unable to fit through 2-tile high spaces in the 主機版.
- Effective when used along with 手榴彈s against 毀滅者 and 世界吞噬怪.
- Using boulders is an efficient way to kill NPCs, should one wish to do that.
- Boulders are the only placeable objects that cannot be picked up again once placed, as 錘s have no effect on them, and mining them with a 鎬 or 鑽頭 only causes them to roll.
- At full tilt, boulders roll faster than a running player with every conceivable speed boost applied. Using a 懸浮板 or Asphalt can however overcome them.
- 1.3：Damage from Boulders is now reduced by player defenses (Boulder damage previously ignored player defense).
- 1.2.3：Boulders with Chests on them no longer crash the game if the boulder is hit.
- 1.2：Stack limit raised from 250 to 999.