I used to have a printout of https://www.michaelbach.de/ot/mot-snakes/index.html over my desk. People got so freaked out by a piece of paper "moving" that there were people who literally refused to go to my desk. :-)
I used to have some of these tiled on my desktop so that in true BOFH style when someone came to pester me I could click show desktop and they would forget what they came to bother me about.
People just being freaked out was fine with me. Making them actually sick would not have been.