Every time I try to run my main scene, it gives an error that says 'Invalid Call: Non-existent function 'initialize' in base CharacterBody3D

“Invalid Call. Non-existent function ‘initialize’ in base CharacterBody3D (mob.gd).”

I am a complete beginner and I’ve looked elsewhere on the internet and have not found a solution. How do I fix this error so I can run the scene?

initialize is not a method on CharacterBody3D or your script mob.gd

Can you paste your script or explain further what you intend to do?