# Panic
NetHack panics when it reaches a state where it is completely impossible to continue the current session. Panicking terminates the game immediately with the messages "Oops... Suddenly, the dungeon collapses."[1] If the game can be recovered to a point where it was continuable, a backup saved game may be generated.
Panicking is referenced in a rumor: "They say that collapsing a dungeon often creates a panic."

Mechanics
It is very rare for a normal game to result in a panic; however, several bugs in NetHack 3.4.3 revolve around panics, usually involving monsters or objects being destroyed under unusual circumstances; exceptions include C343-23, "Dungeon collapses after vault guard fails to lead you out.", and C343-383, "Applying a bullwhip while hero is at edge of map may cause a panic or crash."
It is handled through the panic() function in Source:end.c.
Less serious errors can result in an impossible message.
In exceedingly rare circumstances, NetHack may Segfault instead, without any chance to continue.

Variants
In NetHack 4, NetHack Fourk and FIQHack, a panic gives the player a choice of how to proceed. One option is to reload the game from a backup save (potentially allowing the game to continue, as long as the sequence of events leading up to the panic are not repeated). The other is to leave the save file in its current state, containing a record of all events up to the panic; this leaves the game unplayable in the short term, but may permit gameplay to resume from that point via playing on some future updated game executable in which the bug is fixed.

This page may need to be updated for the current version of NetHack.
It may contain text specific to NetHack 3.4.3. Information on this page may be out of date.
Editors: After reviewing this page and making necessary edits, please change the {{nethack-343}} tag to the current version's tag or {{noversion}} as appropriate.

↑ end.c in NetHack 3.4.3, line 260