Looney Tunes is an American animated series of comedy short films produced by Warner Bros. from 1930 to 1969 during the golden age of American animation, alongside its sister series Merrie Melodies. It was known for introducing such famous cartoon characters as Bugs Bunny, Daffy Duck, Porky Pig, Elmer Fudd, Tweety, Sylvester, Granny, Yosemite Sam, Foghorn Leghorn, Marvin the Martian, Pepé Le Pew, Speedy Gonzales, Tasmanian Devil, Road Runner, Wile E. Coyote and many others.
While the proper spelling of the show is Looney Tunes, many people remember the spelling being Looney Toons, as in cartoons.
There are many residual photographs of this Mandela Effect, but the challenge in proving their authenticity depends on proving they are not simply typos.
Mandela Effect Database
The most common explanation for this Mandela Effect is that the show was named Looney Tunes as a direct parody of another Disney show, Silly Symphonies and Merry Melodies.  Furthermore, the term "toon" used to describe a cartoon was not popularized until the 1980's, years after Looney Tunes was released. 
- This is why it's called Looney Tunes|https://www.reddit.com/r/MandelaEffect/comments/63rb81/this_is_why_its_called_looney_tunes/