Okay kiddo, so have you ever heard of the phrase "everyone is equal"? It means that no matter who you are, you have the same rights as everyone else. That's kind of like what the phrase "erga omnes" means.
"Erga omnes" is a Latin phrase that basically means "towards everyone." In legal terms, it means that certain rules or agreements apply to everyone, not just a select few. So, let's say there's a law that says you can't steal. That law applies to everyone, and you can't say "I'm special, it doesn't apply to me!"
Another example: let's say there's a treaty (which is like an agreement between countries) that says no one can use chemical weapons. That treaty applies to all the countries that signed it, not just a few of them.
So, "erga omnes" means that certain rules, laws, or agreements apply to everyone equally, and no one can say they're exempt from them. It's like the ultimate fairness rule!