I've never seen the dungeon generate like this before and thought I'd share. I was worried I would disturb the surface sand trying to get in but thankfully there was plenty of hardened sand to prevent that. Seed is here as well in case you wanna check it out.
Seed: 2.2.1.0.abandoned manors|beam me up|sandy britches|954234915
by Monst3rP3nguin