How to only allow one specific type of entity per world

Hi, everyone!

I would like to know if there is a way for me to only allow one type of specific entity per world. What I mean by this is, I have a custom entity I'm making, but I only want one of it per world. There should only be one of this entity per world, else it will be too overpowered. If anyone knows how to do this, please reply to this forum!

Thanks!