Tommy Toilet first appeared on the back of an issue of a 1971 Hytone Comix. He later reappeared on an infamous poster with some good advice for staying fresh and clean! It's good clean fun! It's hygienic! It's considerate of others!
Robert Crumb got his start making comics along with his three other siblings but his first official published work was as an illustrator for American Greetings cards where he mastered his Zipatone shading technique. He moved to San Francisco though and started making Zap Comix which kind of started the whole Underground comix thing. He got real popular off of his Fritz the Cat and Mr. Natural cartoons, oh and he made those Keep On Truckin' comics! They gave him an Eisner award in 1991 and somebody did a documentary on him in 1994.
Crumb was good friends with Harvey Pekar, and he helped launch Pekar's comics career by drawing the first issues of his American Splendor comics for him. Harvey went on to be a bit of a success too, appearing on David Letterman a few times, writing biography cartoons and they made a movie out of him with Paul Giamatti.
Anyway, Crumb was a musician too and he loved all kinds of stuff like bluegrass, jazz, and blues. He played some music but he's probably better known in that world for the album covers he drew. His most famous album covers were for records like Cheap Thrills by Big Brother and the Holding Company and a greatest hits album called The Music Never Stopped: Roots of the Grateful Dead.