/fan-ˈdaŋ-(ˌ)gō ȯn kȯr/
[UNIX/C hackers, from the Mexican dance]
n. In C, a wild pointer that runs out of bounds, causing a core dump, or corrupts the malloc(3) arena in such a way as to cause mysterious failures later on, is sometimes said to have 'done a fandango on core'. On low-end personal machines without an MMU, this can corrupt the OS itself, causing massive lossage. Other frenetic dances such as the rhumba, cha-cha, or watusi, may be substituted.
See aliasing bug, precedence lossage, smash the stack, memory leak, overrun screw, core.