Knockouts don't get much more terrifying than this.

A well-placed knee is possibly the most devastating strike in MMA.

Adding a collision to that, with one fighter catching the other as he's moving forward, makes it even more terrifying.

And when that collision comes as one fighter is somersaulting into a leglock attempt, called the Imanari Roll? Well, you get this.

After losing the first two rounds of their fight at UFC Stockholm, Damir Hadzovic caught Marcin Held with a knee as the latter was attempting an Imanari Roll. Watch (and listen to) the vicious finish above.

It's a huge win for Hadzovic that sets his ship on the right path following an ugly debut. Held, unfortunately, now finds himself in dire straits with a 0-3 UFC record.