You know how when you play a game, there are rules that everyone has to follow? Well, just like that, in life there are rules too. These rules are called laws, and they tell us what we can and cannot do.
Sometimes, people can create things like songs or videos or written stories, and they want to make sure that nobody else copies their work without permission. They want to have the power to say who can use their creation and how. This is where "all rights reversed" comes in.
"All rights reversed" means that instead of the person who made something having all the control over who can use it (like the rules of a game), they give up all their power and let anyone and everyone do whatever they want with their creation.
This sounds a bit crazy, right? Well, sometimes people want to do this because they believe that everybody should have equal access to ideas and knowledge. It's a bit like sharing a toy or a cake with all your friends, making sure everyone gets a piece.
So, just like how you sometimes play a game with no rules where everyone can do whatever they want, sometimes people make things with "all rights reversed" which means anyone can use it however they want.