 Which characters were in a unique canonical cartoon from the "Looney Tunes" and "Merrie Melodies" series?
Soup or Sonic: Soup or Sonic is an animated cartoon distributed in the Merrie Melodies series, starring Wile E. Coyote and the Road Runner. Soup or Sonic:  This is the only canonical cartoon in which Wile E. Coyote catches the Roadrunner without him escaping afterward. Wile E. Coyote and the Road Runner: Wile E. Coyote (also known simply as "The Coyote") and the Road Runner are a duo of characters from the "Looney Tunes" and "Merrie Melodies" series of cartoons.
Wile E. Coyote and the Road Runner