Steal My Best Trap: The Exploding Rolling Boulder Trap

[ThePlanarDM]

I wrote up the best trap I’ve ever created for a Dungeons and Dragons game: The Exploding Rolling Boulder Trap. (http://theplanardm.com/the-famous-exploding-rolling-boulder-trap-dd/)

The article has a diagram and detailed description on how to run the trap, which is appropriate for PCs of any level (though higher level PCs are more likely to get around it).

Summary: Not Your Ordinary Rolling Boulder Trap


This trap plays on the traditional rolling boulder trap made famous by Indiana Jones.
The “boulder” that rolls down a hallway threatening to crush the PCs in this scenario is in fact a large pinata-like balloon of explosive gas shaped like a boulder.
The Kobolds’ goal is to shoot the boulder using their fire arrows when the maximum number of PCs are within the blast radius of the fireball this creates.
To prevent PCs from simply running away, the Kobolds have devised another devious trick--alcoves carved into the sides of the hallway that trick unwary PCs into thinking they can dodge out of the way of the boulder’s path.
But the alcoves are not merely mechanisms to corral the maximum number of PCs into the radius of an exploding fireball--they are pit traps lined with poisoned spikes!

[Ranger Wolfe]

This is evil. I love it.

[Quietus]

That's pretty great, but as a DM, I don't want to just drop a "Gotcha!" on the players. I'd definitely have obvious scorch marks near the alcoves along the hallway, just to give the PCs a fighting chance of realizing something is up.

[JackPhoenix]

That's pretty great, but as a DM, I don't want to just drop a "Gotcha!" on the players. I'd definitely have obvious scorch marks near the alcoves along the hallway, just to give the PCs a fighting chance of realizing something is up.

Well, gas baloon wouldn't act the same way boulder would. It would be much lighter, and not made of stone (the goblins want to be able to set it off, after all). It wouldn't roll like a stone, it wouldn't make noise like a stone, there wouldn't be ground tremors tons of rock would make while rolling.

[Grod_The_Giant]

The only way this could be any better would be if it was somehow also full of spiders.

[Darc_Vader]

The only way this could be any better would be if it was somehow also full of spiders.

Lever activated trapdoors at the top of the alcoves that dump spiders on the unlucky fools who thought to avoid the ‘boulder’ once the explosion has gone off.

[Demonslayer666]

Add a doorway that opens into a hallway/alcove with a gelatinous cube once the trap is triggered.

[Trickery]

The only way this could be any better would be if it was somehow also full of spiders.

Twist: the boulder is actually a giant mechanical spider.

[Goggalor]

It is inventive, but how is the "boulder" durable enough to not simply "pop" when the kobolds go to roll it down the hill? However, if it is somehow durable enough to roll down the hill without popping on its own while presumably crashing down the hallway to give the illusion of a "boulder", then I have to wonder how a few simple fire arrows would then penetrate it. :smallconfused:

[Galithar]

Twist!! The boulder is not actually a balloon, but rather an elaborate steel shelled bomb coated with a gunpowder derivative that is highly flammable and an instant ignition fuse on one end of the 'boulder'.

When the 'boulder' is struck by anything flaming the outer coating burns away within 6 seconds. (Detonating after the boulder moves the next time). When the outer coating burns away it also lights a small fuse on one end that leads to the core of the 'boulder'. The result is an instant Fireball explosion. Additionally the boulder hitting you still has enough weight to deal minor damage, and will continue to roll to the end of the hall after detonating.

[Trickery]

Twist! The boulder isn't moving. It's an immovable boulder, and the dungeon is moving. Because the dungeon is spiders.

[Darc_Vader]

Twist! The boulder isn't moving. It's an immovable boulder, and the dungeon is moving. Because the dungeon is spiders.

Ok, that one caught me off guard. Best use of spiders so far.

[Laserlight]

Remember the holes in the walls that shot darts? Add those. Each dart that hits subtracts 5ft from your movement.

Put in a real boulder first. The players have to cross a balance beam over a pit, and the first boulder drops into the pit (possibly onto some PCs). The second "boulder" is triggered when the first one gets to the pit.

I used a Gelatinous Cube Sphere. The PCs went around a corner and thought they were safe. "No, the ball makes the turn, it is following you."