Take all of the ink pens on his desk and swap around the tubes of ink to be mismatched with the color of the pen. ie: A supposidly black pen will write in red, blue writes black, etc.
Change the paths of his desktop icons so they open different programs.
Bring in a giant pile of hay. Hide small objects from his desk in it. (Might get a giant "WTF, you're fired" from co-workers/bosses)
Create a screensaver that looks like a format screen, so everytime he turns his back for a few minutes he freaks out.
If things get nasty, always make sure to revert to pooping in one of his drawers.
Change the paths of his desktop icons so they open different programs.
Bring in a giant pile of hay. Hide small objects from his desk in it. (Might get a giant "WTF, you're fired" from co-workers/bosses)
Create a screensaver that looks like a format screen, so everytime he turns his back for a few minutes he freaks out.
If things get nasty, always make sure to revert to pooping in one of his drawers.