Third Time’s The Charm
Haha, I once convinced a guy that shortly after puberty you get a third testicle which makes the sperm able to create a baby. The guy believe this for a little over a week, each time he asked someone about this I had already gotten to them first and asked them to go along with it.
I felt bad after a bit, as he was getting really worried as he had recently gone through puberty and hadn’t gotten his third testicle yet. So I told him the truth. Story credit: Reddit / scealfada