The mathematical version of the Wild West standoff! Dig into the history of any mathematical theorem or physical law, and you'll inevitably find that either Euler or Gauss probably did it first. These two were basically the mathematical equivalent of that kid who raises their hand for every question in class.
The creepy face just captures that moment when you realize your "new discovery" was actually solved by one of these guys 200+ years ago. Gauss casually invented entire fields of mathematics before breakfast, while Euler was so prolific that mathematicians started naming things after the second person who discovered them just to give others a chance.