Stories about which German nobleman appeared in "Handbook for Fun-loving People", a humor magazine, in 1781?

prank. Also the more sinister disorder Münchhausen's by proxy, where the illness is created in another, typically a child.

little b, He is also the source of the name for the disorder known as Munchhausen's Syndrome in which a person feigns illness, disease, or injury - often severe - for attention

I have never heard of this man in the picture