Why would Rick mention a "dark eyeliner"? Is it a stereotype for a magician, perhaps?
Answer from a Native speaker
I don't think it's a well-known stereotype, but since magicians do dress up for performances, I'd say it can be associated with them! The main point here is that he's referencing the costumes and performative aspect of magic, whereas he does science which is more about thinking and being analytical. He's contrasting the differences. Ex: When I started performing magic on stage, I wore makeup. Ex: If you're a magician, don't you need a hat and a rabbit?