Obstacle/Hazard

Effect

Acid tank

1d6 damage per round, or 10d6 per round for total immersion; plus poison fumes.

Antimagic field

Negates all spells or magical effects.

Dimensional anchor trap

Blocks bodily extradimensional travel.

Hurricane-force winds

Ranged attacks impossible, flight virtually impossible.

Lava pit

2d6 damage per round, or 20d6 per round for total immersion; plus continuing damage.

Permanent prismatic sphere

Requires seven different spells to bypass.

Permanent solid fog

Move at one-tenth normal speed, –2 penalty on attack and damage (good when coupled with incorporeal monsters).

Permanent wall of force

Blocks most spells and ethereal travel, can’t be dispelled.

Three-dimensional dungeons

Levitation/flying required to move between areas.

Unconnected rooms

Teleportation required to move between areas.

Variable gravity

As reverse gravity, but direction random each round.