unattended - I should know better by now. I work with some little sh*ts.:-P 
Back about Windows 95 era, somebody changed my hourglass to a bad finger icon. 😀
Nice. Very nice. Does she have a sister?
Man, your desk is way too clean!
The main lesson to learn here is that if you just has to go out drankin, do NOT allow them to talk you into wearing the red tutu. Not even for "just a little while". This ALWAYS leads to interesting wallpaper on your computer.
I did that to someone once. But I removed all of their desktop icons (put them in a safe place), set the taskbar to auto-hide, turned off the screensaver and replaced the wallpaper with an image of a BSoD.
Hilarity ensued.
I edited a fellow employee's windows 98 batch file to load a web page full screen on boot. Selected web page was an animation of the HAL 9000 announcing it had taken control. He was not very computer literate and the next time he started the computer he totally freaked. 
You computer pranksters need to learn not to do such things to a vengeful, vindictive, interest collecting, uncivilized and not quite sane person. The splatters are very difficult to remove.
B-)
