Black screen/screen
A completely black page with no cursor. In full screen the computer looks turned off.
Pick your fake prank.
Make the computer look switched off, stuck in an update that never ends, or crashed with a blue screen.
Choose one
Fake update/update
Windows 10/11 or Mac update, or a Samsung phone or iPhone installing an update. You choose how long it takes and what percent it's at.
Blue screen of death/bsod
Windows “Your PC ran into a problem” with the % complete counter, or the grey Mac “You need to restart” screen.