Just as there’s a difference between what’s required of stage actors and film actors, voice acting is an art unto itself. Without the benefit of visible expression—a shrug here, and eye roll there—or the ability to use one’s body to help tell a story, the voices behind your favorite animated characters need to rely on instinct, inflection, and good old-fashioned storytelling to form a connection with their audience. Which is probably why the most successful voice actors are so in demand, as evidenced by the fact that that so many of them work on multiple projects at once.

Take Dan Castellaneta, for example. While he’s best known as the voice of The Simpsons’ patriarch Homer, he also provides the vocals for Grandpa Simpson, Barney Gumble, Krusty the Clown, Groundskeeper Willie, Mayor Quimby, and other characters on the long-running hit series. But Castellaneta’s workload doesn’t end there; from 1996 to 2004 he played Arnold’s Grandpa on Hey Arnold! and voiced The Robot Devil on Futurama from 1999 to 2013.

Fivesquid recently paid tribute to the hardest working voices in show business with an extensive infographic detailing the singular voices behind multiple characters—some of which may surprise you.

 Infographic courtesy fivesquid.