|Printable ASCII characters|
In NetHack, the number zero (0 ) serves the following purposes:
- 0 is used to represent the heavy iron ball that appears when being punished.
- 0 and the other numeric keys 1–9 can be used to specify a numeric prefix for a command or in a menu.
- A popular choice for the boulder option is to set it to 0, as it is considered a better graphic representation of boulders and far easier to see than the backtick, `.
- Unimplemented code that handles warning for monsters with a level below four would represent such monsters with a 0, and describes them as causing you "worry".
In hack121, a variant of Jay Fenlason's Hack, 0 was used to represent an octopus.
GruntHack implements the unusued code for warning of monsters that are level four and below described above, representing them with 0.
DynaHack uses the 0 glyph for boulders by default, rather than `.