Yesterday a friend put some gas in, with no problem. Today I locked the keys in the car, with it running, and the person came in about 45 minutes, and turned off the car before it got into the red zone of being out of fuel.

I went to go fill the tank, and there is a brass colored thing blocking the inner entrance (so fuel won't go in). It seems 3D, and like it has a curved corner.

Does anyone have a clue what might be blocking it?
Is this part of a security measure that the car has in it?

I appreciate any insight and help offered here.

 

Never mind