Wow! That’s almost beyond my understanding of physics! If you zoom this ‘gif’ you can see that there is no spin at all on the ball. It must work because of the unstable slipstream of air behind it, pulling it back and forth from the back side! …anybody?
It’s a knuckleball not a screwball, the pitcher appears to be Cy Young winner RA Dickey, a knuckleball pitcher
This was from the game in June when Dickey threw a one-hitter against the Rays.