It kind of reminds me of a thing from the Apple IIe. If you were running a program on that machine and it crashed, it would often crash into this built-in micro debugger mode that gave you a * prompt. The normal boot-up ] prompt accepted BASIC and PRODOS commands, but the * prompt was for working with the Apple microassembler, and it was NOT user-friendly to the average young geek. So I learned exactly one command, which was 3D0G. My understanding was that this was an unconditional jump command to the place that PRODOS was normally loaded into memory at boot, so if the program hadn’t overwritten that, it would get you back to the ] prompt. (Otherwise you had to turn the computer off and on again so it would reload from ROM, which wasn’t a huge problem anyway, but this was a bit faster.) But I’m not actually sure exactly what it did. Anyway, it was memorable enough (since the zero looked close to an O that I could remember it as “three dogs”) that I held on to it. Not actually important, just, y’know, kinda fun.