wtf was this huge flash on my screen for?

it said something like "Round we go" which is a thresh quote and it FILLED THE ENTIRE SCREEN. I was playing Darius in a game deciding fight, and it popped up right as I was going to R someone. When it popped up, I completely lost track of where they were, costing us the game. Is this nessacery? Is this the eternals shit? CAN I PLEASE DISABLE IT>??????