Road Runner is a Looney Tunes character who gets chased by Wile E. Coyote & the only thing he says is "Beep! Beep!".
He appeared in the Slappy Squirrel cartoon "Little Old Slappy from Pasadena" in which gets another taste of humiliation when he is outrun by Slappy's car, and after Wiley gets hit by Slappy he holds up a sign saying "I quit"—immediately afterward, Buttons, who was launched into the air during a previous gag, lands squarely on top of him.
In Bumbie's Mom he was getting chased by Wile E. Coyote & escapes him after Wile E gets hit by a truck.
During the opening sequence in "Episode 64", an animator, who resembles Chuck Jones, is seen painting a picture of Road Runner.
He is also mentioned, but not seen in "Please Please Please Get A Life Foundation".
He is among the cartoon characters seen in Dot's musical number in the reboot episode, "Suffragette City", popping his tongue out twice as Dot mentions him.