Vaudevillian Eddie Cantor was a major star in musicals in the early '30s, and his bulging eyes and swishy hand movements were prime cartoon material. Here's a gag that only makes sense if you're familiar with Cantor:

Silent comic Charlie Chaplin was a big influence on cartoon slapstick. This bit from MODERN TIMES, where he goes crazy with some wrenches, was directly referenced in a Porky Pig cartoon (look for an appearance from another classic comedian, W.C. Fields).

English actor Charles Laughton was often parodied in cartoons for his tyrannical performance as Captain Bligh in MUTINY ON THE BOUNTY. When Bugs Bunny or some other character says, "it's mutiny, Mr. Christian," they're referencing Laughton.

Few people know effeminate comedian Joe Besser by name, but his catchphrases "ya craaazy" and "not so faaast" show up in countless old cartoons. It's exciting to finally watch these clips and see what they were riffing on.

Entertainer Al Jolson starred in the very first talkie THE JAZZ SINGER back in 1927. Cartoons parodied him constantly, and the Merrie Melodies classic I LOVE TO SINGA is a direct parody of THE JAZZ SINGER.

French musical star Maurice Chevalier is best known today for supporting roles in films like GIGI (and for singing the title tune of Disney's ARISTOCATS), but he was a popular leading man in his day. Here's Betty Boop, voiced by Mae Questel, doing a dead-on impersonation.

The sophisticated voice of Oscar-winning English actor Ronald Colman was often invoked in cartoons for urbane characters. I'm sure Colman never could've predicted he would be turned into the bumbling stepfather of a stammering buzzard.

Crooner Frank Sinatra shows up in tons of cartoons, usually with girls swooning over him and usually bizarrely skinny. These running gags got progressively absurd with every film.

Radio star Jack Benny was frequently caricatured in WB cartoons, and he even lent his voice to one! Despite his popular cheapskate character, he didn't want any pay and only asked for a print of the film. Note that in this live-action clip he shares the screen with Mel Blanc.

Red Skelton's radio show, particularly his Mean Widdle Kid character, spawned numerous Looney Tunes references. "If I dood it, I get a whippin," "Let's not get nosy, bub," "He bwoke my wittle head," and "He don't know me very well, do he?" all come from Skelton.

One reference I always wondered about as a kid was when cartoon characters would ask, "How do you dooooo?" in a silly accent. Turns out they were imitating Bert Gordon, known as "the Mad Russian" on the Eddie Cantor Program. Here's a rare screen appearance of Gordon:

Jewish comic Fanny Brice was a huge star from the Ziegfeld Follies and even inspired the 1964 biographical musical FUNNY GIRL. Her "Baby Snooks" character on radio was a source of inspiration for cartoons of various studios.

Comedian Harold Peary was extremely popular on the radio as the pompous character the Great Gildersleeve. His distinctive voice was used for several cartoons, most notably as a sniveling antagonist for Bugs Bunny. (Bugs calls him "the Great Gildersneeze" here.)

Duck-loving goofball Joe Penner is hardly remembered by anyone today, but he was a sensation in the 1930s. Penner's persona inspired the Looney Tunes character Egghead, and his catchphrases ("oh, you nasty man," "don't ever doo that," etc.) show up in countless shorts.

Last one for now: The phrase "mmm... could be" is in about a million Looney Tunes. It comes from the incredibly obscure comedian Artie Auerbach, who played Mr. Kitzel on the radio show AL PEARCE AND HIS GANG. After some digging, I found Auerbach saying the line:

P.S. Here's Artie Auerbach in action as Mr. Kitzel on the Jack Benny Show, singing with the great Mel Blanc, who imitated him so often in cartoons! His "pickle in the middle" song is in my head now, so I pass it along to you people: