Okay kiddo, have you ever watched a movie or played a video game where you heard a really funny scream? That scream is called the Wilhelm Scream! It's a special sound effect that has been used in lots of movies and games since a really long time ago, like over 60 years!
The Wilhelm Scream started in a movie called "Distant Drums" where a man named Wilhelm gets attacked by an alligator and screams in a very funny way. After that, sound designers started to use that same scream in lots of other movies and games. It's like a little secret code for them to use the same sound effect over and over again!
So, whenever you hear that silly scream in a movie or game, you can say "Hey, that's the Wilhelm Scream!" And now you know the story behind it too!