Lethargic Man (anag.)

This sounds familiar, not as an experiment, but as something seen when one accidentally spills a drop or two of water onto a paper where there is writing in ink. Perhaps we learned about it in chemistry but were never given the name? I took a really low level Chemistry in high school(secondary school) because I didn't feel like exerting the extra effort to take on higher level Chemistry(especially since I wasn't so good at math and science). Then again, this sounds like something that in theory at least, could be taught in primary school. Maybe not. Regardless, thank you for the explanation, and I hope that your leg feels better and less bruised soon!