Mike (Cars)

Mike Car: "We're banished, genius! Stuck out here in this wasteland without chains!"
Sullivan Truck: "But, Mike, the Boomobile's in trouble! She needs our help!"
Mike Car: "You're still not listening!"

—Mike Car and Sulley Truck arguing

Mike is a minor character in Cars.

Cars

"Mike is the top scare assistant at Monster Trucks Incorporated. He assists his best friend and number one all time Scarer, Sulley. Mike is a wise crackin' Micro-car who loves joking around more than he loves working, but together the two make a great team."^[1]

He appears in Monster Trucks, Inc.

Tokyo Mater

He and Sulley make a cameo in Tokyo Mater when Mater drifts out of the building.

Trivia

Mike appears in the video game Cars Mater-National Championship along with Sulley, but is voiced by Ivar Brogger instead of Billy Crystal. In the game, he can be played in the Mike and Sulley's Last Laugh levels. He also appears driving around Radiator Springs in exploration mode, as well as in the endscene of Big and Strong Again.
He is based on the character Mike Wazowski from Monsters, Inc.
In Cars Race-O-Rama, he is playable in Guido Kart races.
According to Car Finder, he is a Heebie-Jeebie Buggy Inc. Cycoupe.