Pun

A pun is a form of word play that suggests two or more meanings, by exploiting multiple meanings of words, or of similar-sounding words, for an intended humorous or rhetorical effect. NetHack contains many puns - items or monsters that behave in ways not necessarily consistent with their real-world or mythological origin, but which make sense based on an ambiguous reading of the name.

Examples

• The Black pudding is considered non-vegetarian, presumably because some types of blood sausage are known as "black pudding".
• A cursed potion of gain level puns on the two different in-game meanings of "Level" to refer to both experience level and depth in the dungeon.
• The loadstone is a pun (dating back to early editions of Dungeons and Dragons) on "lodestone". Sadly, it has no navigational function, but only acts as a heavy load.
• The turn undead effect also derives from Dungeons and Dragons and causes undead monsters to flee. In its beam form, it can also be used to revive corpses - a pun known as the "un-turn dead" effect.
• When polymorphed into a form that can eat metal, eating an amulet of unchanging causes you to revert to your natural form: it "un-changes" you. This is noted as a pun in the source code.
• The substitution of a level teleport trap for the vault teleporter in closets on deeper levels is a pun on the secondary meaning of "aerarium" as "sky".
• Levitating over a sink will cause you to "sink" to the floor.
• The Platinum Yendorian Express Card can be used to "charge" wands.
• Reading a dull spellbook may give the message, "This book is so dull that you can't keep your eyes open," and put you to sleep.
• Etc.

The presence of so many puns is one of the challenges of translating NetHack into other languages.