# Pun
A pun is a form of word play that suggests two or more meanings, by exploiting multiple meanings of words, or similar-sounding words, for an intended humorous or rhetorical effect. NetHack, and by extension its many variants, contains many puns—items or monsters that behave in ways which, while not necessarily consistent with a real-world or mythological origin, make sense based on an ambiguous reading of the name. Some punny features are the result of the development team seeking to add a distinct flavor to the game; others may originate from a different source material, and are more intrinsic to the item or monster in question.
The presence of so many puns is one of the challenges of translating NetHack into other languages.

Examples
The glob of a black pudding is considered non-vegetarian to eat because some types of blood sausage are known as "black pudding", and the default tile even gives it a sausage-like shape.
A cursed potion of gain level plays on the two different in-game meanings of "level" - both experience level and dungeon level (i.e. depth in the dungeon).
The loadstone is a pun on "lodestone", dating back to early editions of Dungeons &amp; Dragons; instead of being a navigation aid, it weighs players down, true to its name.
The turn undead effect also derives from Dungeons &amp; Dragons and causes undead monsters to flee. In its beam form, it can also be used to revive corpses—rather, it turns them "un-dead".
When polymorphed into a form that can eat metal, eating an amulet of unchanging causes you to "un-change" and revert to your natural form. This is explicitly 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 a purported secondary meaning of "aerarium" as "sky". (This appears to be in error, as no evidence has been found for this secondary meaning.)
Levitating over a sink will cause you to "sink" to the floor.
The Platinum Yendorian Express Card, which is named after the American Express charge card, can be used to "charge" wands and other items.
Reading a dull spellbook may put you to sleep. ("This book is so dull that you can't keep your eyes open.")