I drew and used this map last week in a game where the character’s needed the blood of a medusa to break a dark and disturbing curse on a temple that one of the party clerics worshipped at.
Knowing they were up against a medusa made the fight a lot easier, so of course I threw in a twist by making her a powerful creature that was part medusa, part spider (like a medusa / drider cross, if you will). The fight turned into a great running battle through her lair and back into the chasm itself as she moved around with a speed of 360′ (120′ in 3e terms) on the walls and ceiling as well as the floor.
The rest of the complex (reached by the stairs on the left-hand side of the map that lead into the chasm itself from the surface) was inhabited by a tribe of spider-goblins (same stats as bugbears, but with the ability to move on walls and ceilings) who also harried the party.
The only thing I wasn’t 100% pleased about was the map itself. I drew it at a friend’s place, and my usual gel pens had all died so I borrowed an ultra-fine tipped pen. In the end, it made the lines very fine and ends up robbing the map of some of the high contrast I usually achieve – I would have had to draw in the cross-hatching twice as thick to get nearly the same effect as I usually get.