.PANIC File Extension
What is a PANIC file?
File created by the Unix kernel when it detects a fatal error and cannot recover; contains information about the state of the machine when the panic occurred, such as program and memory dump information; used to report and debug computer crashes in Linux and Mac OS X systems; saved in a plain text format.
Mac OS X creates a PANIC file when a kernel panic occurs. If this happens, the screen will dim and the following message will be displayed (in multiple languages): "You need to restart your computer. Hold down the Power button for several seconds or press the Reset button."
In Mac OS X, PANIC files may be viewed using the built-in Console application by expanding the DIAGNOSTIC INFORMATION → System Diagnostic Reports location in the Log List.