Becoming The Joker The Killing Joke DC Comics T-ShirtThis Batman t shirt features an image of The Joker realizing that chemicals have permanently changed his skin, lips, and hair. In the classic graphic novel The Killing Joke, an unnamed engineer quit his job at a chemical plant to become a stand up comedian, only to fail miserably. He agreed to guide two criminals into the plant for a robbery, but when the engineer saw Batman, he jumped into the chemical plant's chemical waste catch basin vat to escape