02/18/2023
I thought it would be cool to ask Chat GPT to generate a random encounter in the Underdark, then see if I could set up the encounter using my models and terrain as if I was going to run this for my table.
This is what I got from Chat GPT
As the adventurers make their way through a dark, twisting cavern, they come across the body of a massive spider, its many legs curled in death. The air is heavy with the scent of decay and the adventurers can hear the sounds of fluttering echoing in the cavern. Just as they are about to examine the spider’s remains, a loud roar shatters the cavern’s silence. An owlbear, its eye blazing with anger, bursts into the chamber and charges toward the party.
So I would need an Underdark chamber (Underdark UDT with UDT walls) with a few entrances, some scatter terrain, a few PC miniatures (let’s say 3), a giant spider, and an owlbear.

Here would be the opening scene with the PCs entering the Underdark cavern:
There is an entrance from the West that the PCs are using to enter the cavern. There is an exit to the East through a larger opening and a small entrance to the North on a raised cliff face (10′ tall). There are several rock outcroppings with mushrooms in the cavern that can be giving off a blue-glowing light (I used a color-changing LED light to set the mood). The fluttering noise echoes throughout the chamber and the PCs cannot tell where it is originating. The body of the dead spider is laying in the center of the cavern.

If any of the party members approaches the dead spider to investigate, the owlbear will roar and enter the cavern from the North entrance on the cliff face. It is crazed and immediately attacks, starting with the PCs near the dead spider (the owlbear thinks the PCs are here to steal its kill). ROLL INITIATIVE!
If it is a low-level party (Level 1 or 2), you can have the owlbear have less HP (maybe it is still a little hurt from the fight with the giant spider). If it is a higher level party, you can add in a 2nd owlbear or more giant spiders (or both!)
Keep on gaming!