Funny story -- the closest shave ever came this last weekend and the party was saved because of a bit of character business.
Our cast of characters: Five PCs making up a pretty standard band, one NPC they don't like and don't trust but need, and a DM (me) who thinks he's come up with a pretty clever little encounter.
The party came across a rope bridge in the mountains with a broken crate and a sign saying "Out to lunch, honor system, everyone pay 25GP." The party, not wanting to get into any trouble, paid. The present NPC, however, didn't bring a lot of money with him and kind of balks. Our dwarf cleric goads him into crossing without paying (I rolled a Wisdom saving throw for the NPC -- I sometimes do this as a save against stupidity -- and he failed). As the NPC steps on to the bridge, the crate lets out an inhuman howl. Yes, it's a Mimic. I always wanted to work one in, but I wanted to do it in such a way that my players wouldn't spent the rest of the campaign poking furniture with sticks.
The Mimic lashes out at the nearest PCs and then starts hopping after the NPC. Roll Initiative. When it comes to the human fighter, he says he'd like to use his action to brace himself against a rock because he's laughing so hard. I'm like, sure, why not? I grab a D12 and stick it on the map as a boulder. After two rounds of combat (with half the players willing to let the Mimic just eat the NPC), the rest of the trap springs. Two Trolls come down.
This is where I screwed up. The encounter had been balanced as Hard with just the two Trolls, but also with the idea that there would be an extra NPC along for the ride (the players drove him off earlier in the session -- ironically, he was the one they wanted to keep). Once I added the Mimic and saw that the party was going to be down by one, I should've pulled the second Troll. I accidentally pushed the whole thing beyond Deadly.
I ended up being really grateful for that boulder. It was positioned in such a way that the Trolls couldn't easily maneuver around it. They couldn't really get to the bridge without circling around the long way. They did nearly kill our wizard and cleric, but the boulder inconvenience gave the party enough time to come up with a plan for escape (involving a Helm of Teleportation they forgot they had). As a bonus, they also managed to kill both Trolls (and the Mimic was tossed off the bridge).
The player who asked for the rock got bonus XP for it.
I usually use dungeon generators for inspiration unless I have a specific idea about layout. I then design the dungeon on graph paper. The final version gets drawn out on a gridded easel pad for actual play.



Dungeons & DragonsClose ShavesAug 30, 2016 at 3:20 PM