Explosive Bolts

 

A sturdy iron door, reinforced by several bolts, is closed.

Mechanical Trap

The bolts are explosive, and will be set off when the door is opened. A DC 14 Wisdom (Perception) check reveals that some of the bolts are screwed in a bit unevenly, as if they are off-threaded. A further examination with a successful DC 14 Intelligence (Investigation) check shows that the bolt heads are separate pieces from the bolts themselves, and are newer. Small scorch marks can be seen on the bolt threads. The door requires a DC 14 Dexterity check with thieves’ tools to unlock. Alternatively, the door has AC 19 and 27 hp. If the door is opened or if the door takes any damage, the bolts explode, firing the tops outwards. All creatures within 15′ take 3d6 fire damage and 2d6 bludgeoning and piercing damage. A successful DC 14 Dexterity saving throw halves the damage from both sources. Disabling the trap requires removing the lock and disconnecting a wire. This requires a DC 16 Dexterity check with thieves’ tools and must be done after the lock is picked. Failure on this check results in the trap being set off.