Problem With Character

Hi, i have a few worlds in my game and i want to have different characters in every world. For example when i set a red ball as character to world 1 then in other world characters turn to red ball too. Any suggestions?

 

You can do as "Color Switch", when the character appears, change for you choose.

 

Thanks for answer @jcalle, could you explain more deeply. How can i do that?
Thanks in advance.

 

I want to make something like when player goes to 2nd world the ball there should be changed immediately. Player shouldn't see that change.