A mix of natural caves, secret passages, and man-made construction, the Oubliette is either a small dungeon of it’s own, or an area off of an existing dungeon.
A statue of the Laughing Knight carved of a magical green stone (touching the stone deals 1d20 damage to any non-chaotic creature) gives the Oubliette it’s name, although the actual origin of the statue and who the Laughing Knight may have been is unknown.
Oubliette of the Laughing Knight was drawn by hand in a single draft in The Holly King, a small notebook I picked up at the dollar store. It was drawn using a Zebra 0.7mm Gel Pen.
If you like the Oubliette of the Laughing Knight and maps like it, check out Dyson’s Delves, a book of similar maps and adventures.