Colman's Mustard in Breaking Bad Season 2 Episode 7: Negro y Azul (2009)

As a one-time award winner for his chemistry skills, Walt is smart, but he didn’t expect to be pulled into the dangerous drug trade. A high school chemistry teacher with terminal lung cancer, Walt teams up with Jesse, a former student who’s made a lot of bad decisions himself, to make money by manufacturing and selling meth. What starts out in the back of the car as an illegal money-making hobby eventually becomes his true calling.