(There's no video for Sproing (prank) yet. Please contribute to MR and add a video now!)
Sproing is a neat old system extension prank that once placed in System Folder > Extensions and the Mac rebooted, makes the mouse cursor spring around like crazy. Every move you do with your cursor will be spring-loaded, that is going up, down, left or right and the more force you move the mouse cursor, the strongest Sproing will bounce the cursor around! It's pretty annoying while trying to access the menubar or moving files around!
Sproing was part of The Macintosh Joker book/disk publication in 1993.
Sproing.sit (2.34 KiB / 2.4 KB)
Sproing system extension / compressed w/ Stuffit
System Extension, place it in System Folder > Extensions
Tested on Mac OS 9.0.4 and Mac OS 9.2.2 but will work on way older Mac OS versions too.
Emulating this? It should run fine under: Basilisk II