I've found an Easter Egg (if it deserves that term) in Mac OS X 10.3 "Panther". Mac OS X ships with a command line utility called
appleping which enables you to ping machines on an AppleTalk network (as opposed to standard TCP networks). AppleTalk is rapidly becoming a thing of the past, but Apple has kept this utility in Mac OS X.
If you open a Terminal window and type
appleping and then press enter you will receive a usage message from the program which is as follows:
applepingutility has at least been present since the release of the incomplete Mac OS X Server 1.0, circa 1999, but may date to earlier Apple UNIX efforts, say mkLinux or A/UX.
Usage: appleping net.node [data size] [npackets] or: appleping name:type@zone [data size] [npackets] examples: appleping 'John Doe:Macintosh SE@EndZone' or: appleping 6b16.5