Crystal and Goodman pulled off brilliant, animated on-screen chemistry with the 2001 Pixar film Monsters, Inc. in which we see how Mike and Sulley save their city from an evil plan.

At the Monsters University press day in May, the duo spoke to Hypable about why their characters work so well together.

“They complete each other, in a way,” said Goodman who voices Sulley. “I think Sulley really, really needs Mike Wazowski. It makes him complete, lets him know – lets the air out of him a little bit. Especially in this film, when they’re not completely formed monsters yet, they learn from each other. They learn how to adapt, how to let go of their pre-conceived notions of themselves and of the world. They’re good for each other.”

Crystal added that the magic they create requires more than simple reading of dialogue. “We’re not just reading lines; we’re performing them, and we’re playing them, and we feel them. I think that’s why their relationship on screen is really great because it’s a real thing.”

Perhaps the relationship works so well because they get genuine enjoyment out of reprising these roles. Crystal admitted that out of all of his roles in his movie career, Mike is the character he’s enjoyed doing most.

“It was so fun to revisit them at this time in their lives. It was such a brilliant idea to put them in that time period where they’re about to become who they’re gonna become. That’s what was so interesting to me.”

Monsters University opens in theaters on June 21.