"Planet Zog" is not a real planet. It's likely a fictional planet from a book, movie, or game.

To find out its size, you would need to:

* Identify the source material: What book, movie, or game is "Planet Zog" from?

* Consult the source: Look for information on the size of the planet in the source material, or possibly in online resources about the fictional world.

If you can provide more information about where you encountered "Planet Zog", I might be able to help you find its size!