The alert comes from the default sound scheme in Microsoft Windows 7, released in 2009, where Critical Battery Alarm was one of several short cues for system events. As Windows clips were ripped and shared on soundboards and in video edits, this tiny warning survived long after many users moved to newer systems. It now works less as a real laptop warning and more as a shared error sound joke, borrowed whenever a creator needs an instantly understood signal for low power, failure or shutdown.