It could be part of the cartoon's story or character trait. Maybe the dog is having fun or trying to communicate something in a unique way. Or, it could just be a random act for comedic effect.
Maybe it's just being playful or trying to show some kind of cool gesture.
The reason the cartoon dog is throwing up could be a variety of things. It could have gotten into some spoiled food, or it could be a part of a funny storyline. Maybe it was exposed to a toxin or has an underlying illness. Who knows, it's a cartoon after all!
Maybe your dog ate something bad in the cartoon world or got sick. That could be the reason for the throwing up.
Maybe he's trying to get rid of something or playing a game.
The cartoon boy might be throwing because he's angry and wants to express his frustration. Or perhaps he's participating in a sport or competition.
The cartoon woman might be throwing something to protect herself or to get rid of something she doesn't want. Maybe it's part of a funny scene or a crazy adventure.
Maybe it's for some kind of comical effect or to show a funny and odd situation.
Maybe it's expressing love or showing affection to someone.
Maybe the kid is just having fun or being a bit naughty.
Maybe the baby ate something bad or has a stomach bug.
I have no idea. That's a really disturbing and strange concept for a cartoon.