Little Red Walking Hood (1937)

This short is one of Elmer Fudd's first cartoons and it's a Merrie Melodies retelling of Little Red Riding Hood. The story follows the traditional fairy tale until two shadowy figures appear in the corner. The Wolf even says through gritted teeth "Hey Red, just a minute. Let's wait until these people here get seated and we'll go on with this thing." Once the audience members finish walking across the screen and sit down, the Wolf and Red Walking Hood resume their fight. This moment was a clear call out of bad audience etiquette, perhaps the most tame call out of this list.

Cinderella Meets Fella (1938)

Another Merrie Melodies fairy tale retelling, featuring Elmer Fudd as Prince Charming. He gets to Cinderella's house and she left a note saying she got tired of waiting and went to see a Warner Bros. show instead. Elmer starts crying when a girl stands up in the audience and says "Here I am! Here I am in the guest row! Keep your shirt on, I'll be right up!" and then Cinderella walks across the screen and then onto the screen, reunited with her prince. 

The Mice Will Play (1938)

This Merrie Melodies short is about the wacky hijinks that laboratory mice get up to when the scientists are gone. A group of mice sneak up on another mouse and try to stab him with a syringe when an audience member jumps up and screams "Don't do that!". The mice hear them and drop the syringe, saying "Aw, we never have any fun!" This moment was less about theater etiquette and more about taking the audience by surprise and including their voice in the short.

Daffy Duck & Egghead (1938)

This moment was 100% about audience etiquette. Egghead is hunting ducks when an audience member stands up and tries to move across the screen, prompting Egghead to say "Sit down! Sit down, there's a duck in there! Sit down!". The audience member sits down, and then gets up and tries again, bringing a third shushing and admonishment from Egghead. On the third attempt, Egghead shoots the audience member dead. 

Cracked Ice (1938)

This Merrie Melodies short is about an ice skating competition where a pig, Mr. Squeal falls down. While we don't see a mystery audience member walking across the screen - we hear them loudly laughing. Mr. Squeal gets back up and says "Say, who's heckling me? So it's you, my diminutive little child. What are you doing down there in the third row?" This audience-call out was meant to catch the audience off guard and take them by surprise, ensuring even more laughs.

A Feud There Was (1938)

This Hatfields and McCoys themed Merrie Melodies short - where Elmer Fudd is called in as a peacekeeper to broker a truce between the two warring factions. One of the shooting hillbillies shouts "I'll shorn them no good Weavers! I hates them to pieces - is there a Weaver in the audience?" to which an audience member stands up in the corner and shouts back "Yeah, you skunk!" and shoots the hillbilly. The Weaver audience member returns at the end to shoot at Elmer Fudd.

Thugs with Dirty Mugs (1939)

Gang leader Killer Diller leads a round of bank robberies. While the gang meets an audience member gets up to leave. Killer spots them and says "Where do you think you're goin'? Well, you sit right back down until this thing's over, see?" then he whispers to his cronies "You know, that mug's trying to get out of the theater to squeal to the cops!"

Well, wouldn't you know that the next scene is in a police station and the same audience member jumps up and tells the investigator Killer Diller's plans. The investigator responds "Thanks! You little tattle tail!"

Rhapsody Rabbit (1946)

Then, there was a break in audience member involvement. There were still plenty of fourth-wall breaks (especially from Bugs looking at the audience and saying "Ain't I a little stinker?") but there were not as many calling out the audience moments in Looney Tunes or Merrie Melodies. That was until Rhapsody Rabbit where an audience member loudly coughed as Bugs was going to begin his piano performance. Without a word, Bugs stands up, pulls out a gun, and shoots the coughing audience member. And then continues with the performance like nothing happened.

Rabbit Every Monday (1951)

Bugs Bunny is roasting carrots and the smell is so delicious that it attracts Yosemite Sam, who is hunting rabbits. An audience member gets up and Yosemite Sam says "Oh no you don't! Get back in your seat! The first one that tries to get outta here to warn that rabbit gets his hide blown off!" Then he turns directly at the screen "And that goes for the rest of ya!"

Baton Bunny (1959)

In similar fashion to Rhapsody Rabbit, Bugs is about to begin a musical performance when someone in the audience keeps loudly coughing. This time around, a very agitated Bugs does not choose violence but instead holds up a sign that says "Throw the bum out!". We hear the security guards shuffle in and escort the coughing person out.