It's a shortened and more aggressive version of "who is this" or "who's that." It's often used in a confrontational or questioning manner, implying a sense of defiance or skepticism.
Here's how it's typically used:
* "Whodie who, you ain't got no business here."
* "Whodie who, I don't know you."
It's become a recognizable catchphrase associated with Travis Scott's music and persona, and has also been adopted by other rappers and fans.