One moment, this is all Starlight hears: "Who's your best, best friend?"
The next, stuff happens when they compete for the title of "Starlight Glimmer's Best, Best Friend." I don't need to specify what kind of stuff.

Relationships are questioned, attention is precious, and chaos has started. The competition is on, and Starlight's will to argue is just about the opposite.

Title inspired by I'm Best Friends With My Own Front Door.