Potion of Descent

When this flask is uncorked by hand or shattered by being thrown, the fog that seeps out will temporarily cause the ground in the vicinity to vanish.

These potions are the reason that you should test unknown potions near the down stairway; If you accidentally drink this you will be able to walk right back up. They have the same effect as a pit bloat's attack, opening a temporary hole in the floor. The hole will close over several turns, filling in with empty ground.

The potion is the most versatile among “negative” potions. It can be used to do lots of things.

• Remove terrain features such as creeping death or flammable plants.
• Disarm fire traps.
• Excellent offensive weapon when ascending from floor 26 with the Amulet of Yendor. However, if you are still heading down, and drop a monster through the ground you will still have to face it on the next floor. Another way to fall through the floor is to stumble into a pit trap.
• Dispose of dragon on floor 26.
• Get yourself or allies out from trouble.
• Evacuate a pink jelly from “garden of traps”.
• Dispose of a bog monster or kraken. Both are waterborne, and will be perfectly vulnerable if they fall onto dry land.
• Shake an early ogre from your tail, together with other means of escape like a staff of blinking.
• Divide a nasty group of monsters like twin ogres, twin goblin mystics, or spider+centipede.
• A stone guardian dies when it falls down. So, when the guardian is holding a runic weapon, the best way of getting it is dropping down.