GameCube Service Disc
GameCube Service Disc v1.0/03 was once used by Nintendo World Class Service to test and diagnose problems with the console, Memory Cards, controllers, and can even check the currently-inserted Game Boy Advance game through the GameCube-Game Boy Advance Cable. Nintendo 64 controllers can also be detected, suggesting this is from earlier in the console's development.
As with all Nintendo testing software, the Service Disc contains a plethora of Nintendo-themed content, both used and unused. Bizarrely, there are also respectable logos from the automotive industry, such as Tamiya and Goodyear.
Console revisions post-2003 will boot the Service Disc to an indefinitely-hung black screen, likely done to prevent further servicing after the demise of the Nintendo World Class Service. Remaining copies were taken back by Nintendo and presumably destroyed; as such, few copies saw the light of day.