This is the Ultra Combo glitch in Killer Instinct 2 that allows you to get 80 hit combos with any character. The glitch is triggered when your opponent's health is flashing red and you do your Ultra Combo against them, but your opponent does a Combo Breaker just before the first hit of your Ultra.
With the glitch, and you can hit your opponent from *anywhere* on the screen, so this essentially allows infinite juggling. You can actually do more than 80 hits but the game stops counting at 80. You'll also notice that the clock is frozen during the glitch, so you have as much time as you want to rack up the combo.
