This happened in a one off dungeon crawling session I had with a random group. The setting was split in two, a dungeon and a town. We were a group of adventurers that just came into town and decided to get together to improve our chances of surviving the dungeon, we had a cleric(me), a ranger(in game he was mute), a monk, a sorcerer(I think) and another PC.
Before entering the dungeon the DM let us wander through town and buy anything else we may need from the vendors. Everyone bought what they thought they needed, and I decide to check on a child NPC that's in a dark alley, she was selling one item, a small black disk with a white jewel like stone in the middle. I decide to buy it, it was 50 gp, I had no proficiency that could tell me what it was, but even if it was a worthless trinket, as a cleric I had just helped an unchirn earn money. After this is my PC exchanged the amulet for an unknown potion the monk had bought, having someone check the amulet we found out it was a darkvision amulet, meaning that the monk had double darkvision, the DM allowed him to have double darkvision.
We finally go in the dungeon, and just one of our characters doesn't have darkvision, do he lights up a torch… Roll constitution save for our monk, his double darkvision meant that when a light source appears when it darkness he gets a headache, think using night vision goggles and having someone flash a light directly at you. He managed to pass his rolls.
We move forward and come to a tight corridor, we have to walk in line, the monk goes ahead takes a corner… Roll for constitution and dex, he passes the dex and avoids a fire bolt from a trap he activated, but his misses the constitution roll, meaning that he lost sight from having the fire bolt crossing right in front of him, and the darkvision amulet exploding. We all panic and pull him out the hallway into a room we had confirmed was safe.
A medicine later we determine he is blind, so I decide, as a life domain cleric my PC should try and heal him. DM asks: "Are you going to ask for divine intervention?" since it was the first time playing a cleric I accept, I roll for religion, fail, we all joke how my God is not listening while we are in the dungeon… And we all hear our DM rolling and whispering "Really… Ok" he describes as the monk feels his eyes solidifying and cracking, from the husks that were his eyes come out 2 brown worms, it was a lvl 15 encounter but since we all were lvl 1 he lowered to lvl 8.
What comes after was a hectic fight with some trying to pull the worms out of the monk's head or trying to attack the worms, who were still attached to his head, with weapons. I managed to pull a worm out and moved away from the main group, just enough so no one else was in range. The worm in my hand bite at me, I was unconscious after that bite. The one in the monk's head bite him, and he was also down.
Each turn the worm would bury depper into our unconscious bodies, which meant one automatic failed death save. After just one round both the monk and me were just 1 failed death save away from dying. The sorcerer goes "Our rogue says I should use x spell on them, the range if enough to hit both worms and kill them… But our companions will die as well" and so he cast it. We die.
Then we rolled new PCs and try again. But that was the time my cleric's God pretty said "You are my least favorite cleric, this would be a good chance to get rid of you"