A slam is the only way to register a knockout win with the use of grappling and there have been remarkably few of them throughout the history of the UFC. The vast majority of knockouts obviously come from striking techniques, and the vast majority of finishes that come from grappling are submissions instead. The main reason that there’s so few of them is simply how difficult it is to actually use a slam to knock out an opponent. It requires the competitor doing it to not only have complete control over their opponent, but they also need the ability to generate a tremendous amount of power in the technique.
Another factor is that the vast majority of professional grappling rulesets don’t actually allow competitors to slam one another in the first place. Even seasoned grapplers that have the ability to control opponents with relative ease simply won’t have practiced generating the amount of power required because it isn’t a technique that would have been available to them in the past. Generally, the majority of these finishes come from either wrestlers who are slamming their way out of submissions or athletes with tremendous physical strength who happen to find themselves in the perfect position.
Some of these slam knockout finishes are among the greatest moments in UFC history as well, and several of them have actually been when a title was on the line. Perhaps the most notable recent example of this was when Jessica Andrade took the strawweight title from Rose Namajunas by countering a kimura attempt by spiking her directly on her head. One of the older examples is when Matt Hughes famously knocked out Carlos Newton with a slam to claim the welterweight title for the very first time. It wasn’t always the challenger who finished the fight this wayeither, as Tito Ortiz defended the UFC light-heavyweight title by slamming Evan Tanner unconscious and Frank Shamrock registered his first title-defense against Igor Zinoviev with a brutal slam knockout.
The full compilation of every slam knockout in UFC history was uploaded to the promotion’s official YouTube channel: