Michael John Kricfalusi (/ˌkrɪsfəˈluːsi/; born September 9, 1955), better known as John K., is a Canadian animator, voice actor, creator of the Nickelodeon cartoon series The Ren & Stimpy Show and founder of the animation company Spümcø.

After being fired from The Ren & Stimpy Show by Nickelodeon in 1992, Kricfalusi went on to direct and produce animated television commercials and music videos for entertainers such as the singer Björk and comedy rock duo Tenacious D. In the late 1990s he created the first cartoons made exclusively for the Internet: The Goddamn George Liquor Program and Weekend Pussy Hunt. He returned to television with The Ripping Friends and the adult animation spin-off Ren & Stimpy "Adult Party Cartoon".