Mike Mearls was a lead developer on 4th Edition Dungeons & Dragons and is now the senior manager of the D&D Next team. Mearls co-wrote the 4E Dungeon Master’s Guide 2 with Greg Gorden and Robin D. Laws. He also wrote Mastering Iron Heroes, the game master’s guide to Malhovoc Press’s variant rules for heroic combat. Today, though, Mearls looks back to his early days of AD&D . . . and silent boulders.

Mike Mearls: My funniest GM experience is back in my AD&D days. The characters were exploring the Haunted Halls of Eveningstar, a dungeon in the Forgotten Realms created by Ed Greenwood. This really nasty Thayan illusionist and his cleric of Bane buddy were holed up in the dungeon, and they were epic levels of annoying. The illusionist kept tricking the characters, and the cleric animated the bugbears they defeated and attacked them from behind. Every time the PCs thought they caught a break, one of those two would spring a nasty surprise on them.

Finally, the PCs tracked down the two of them, along with their ogre bodyguard, and gave chase. I had added an escape tunnel to the dungeon that ran down, then up at a steep angle. At the top of the slope was a large boulder that blocked the exit. Between the illusionist and the cleric, they had one spell left: silence, 15′ radius. With the PCs in hot pursuit, the villains came up with a fiendish parting gift. The cleric slapped silence on the boulder, and the ogre pushed it down the slope.

If you’ve played AD&D, you might see what’s coming next. The boulder rolled in utter silence toward the PCs. The next exchange went something like this:

Me: “You rush up the tunnel, when suddenly a massive boulder comes streaking down the slope toward you. It nearly fills the tunnel. Oddly enough, though, it makes no sound as it rushes at you. What do you do?”

Players: “It’s obviously a phantasmal force. They don’t make sound. We keep running!”

SPLAT!

Luckily for the party, nobody was killed, but every PC save for one was knocked unconscious. That has to be my funniest experience, and the closest I’ve come to a TPK with a trap that wasn’t from Tomb of Horrors.