Example Dungeon

Not really a whole dungeon, just one room, but an example of the format.

1: The Snake Room

Entrance

Door is closed, and warded against damage and unlock spells. Depicts a bunch of snakes worshipping at a pyramid. Sunburst on top of pyramid.

Inscription in proto-yuan-ti reads: "The Golden Disc will light the way."

A "keyhole" of sorts seems to want to accept a large, coin-shaped object with a complex embossing of a snake god.

Entrance Trap

As a reward for entering, the party is immediately attacked. A cloud of poison immediately pours forth from the door. The poison causes 1d6 Con damage ots (Fort negates); each breath adds another stack. Assuming one doesn't breathe, 3 consecutive successes can clear the poison (but not cure the damage).

Description

Once past the poison, they can see the room. It's big and square, with a sunken platform at the center. The walls are lined with yuan-ti statues offering organs and bits of things as if in sacrifice to gods.

The inner pit is filled with hundreds (thousands?) of black snakes, writhing over each other. They seem to be in a constant cycle of feeding and sleeping. Beneath the center of the pile is...something...

Monsters

Gotta kill all the shadow asps to unlock the elite. Gotta kill him to move on.

Shadow Asp

There are 10 swarms of shadow asps:

Tortured Couatl

An undead couatl; its body is visible as a translucent form, constantly regenerating from the asp bites; its skeleton seems real enough.

After killing the couatl, it asks you to destroy its skeleton and put it to rest. Yields the Serpent Stone, needed to progress.

Exit

The way out is some sort of complex, interlocking door mechanism.

Four stone snakes coil together to lock the door in place. Each leads to one of the four corners of the room, where the snake's tail forms a lever. At the center of the heads is a slot for the serpent stone.

Marked on the Serpent Stone are dashes indicating numbers: 3 7 11 13

Near each tail is an inscription in yuan-ti:

Solution: