Mini Mario?

[WilsonXXX]

I'm on World 5-4, I'm seeing a lot of things like small doors and tubes, am I missing something? Is there something I should have by now that will turn me into a mini mario?

 

[mosx]

Yes there is a Pixl named Dottie that you need. I am not sure where she is. But you need to flip to 3D to find her.