|A hickey from a plunger|
I do a magic trick where I put a small plunger (sold to be used for iPhones to make watching movies etc. more practical) on my forehead as part of the trick. This looks pretty funny, and I have done it hundreds of times.
Recently, I was asked to do this trick but then in the middle of the trick lots of people showed up and the trick was interrupted. I just kept the plunger stuck to my head for the (fairly long) time it took for people to get in place. The trick still worked fine, but it turns out that if you keep the plunger stuck to your forehead for several minutes, you get a red mark that does not go away.
|Me doing magic with a plunger on my forehead|
I had a perfectly round mark on my forehead for 5 days. This looks pretty weird, and people at work (at the university) commented. It looked so weird that people I do not know that just served me in restaurants also commented. It was a pretty good conversation starter, though, so it was possibly a positive side effect.