Masahiro Sakurai issued a limited-time challenge at the end of the Sakurai Presents Sephiroth livestream in which players would be able to fight against the extremely powerful Final Fantasy 7 villain for a chance to unlock him a week early, however, some seasoned Super Smash Bros. players are speedrunning the challenge beating Sephiroth in a matter of seconds. While Sephiroth is intended to be a very challenging boss battle, Smash Ultimate players are using the game's mechanics to make him look like a walk in the park.
Sephiroth, the main antagonist from Final Fantasy 7, was revealed at The Game Awards 2020 to be the next DLC character to make their way into Super Smash Bros. Ultimate. Masahiro Sakurai, the director of Super Smash Bros., held a separate livestream a week later where he gave an in-depth look at Sephiroth's move set, background, and a new stage. During the character analysis, Sakurai announced that Sephiroth would be available on December 23rd to those who purchase the DLC. However, players who pre-purchase the DLC could unlock Sephiroth early by beating him in a new mode called Sephiroth Challenge.
While this new mode proved to be a challenge for many, veteran Smash players were able to find ways to beat Sephiroth on his hardest difficulty in a matter of seconds. The sheer speed of the Sephiroth fights has sparked a speedrunning competition within the Smash Bros. community to see who can defeat Sephiroth the quickest on Very Hard difficulty. Ross O'Donova aka RubberNinja was able to defeat Sephiroth in five seconds using Kirby's swallow move. Professional Smash Bros. player Hungrybox was able to take down Sephiroth in 2.75 seconds using Mr. Game & Watch's hammer. Other players have posted times as low as 2.1 seconds using various 1-hit KOs.
It's safe to say that this is not how Mr. Sakurai intended for Sephiroth to be treated. In his presentation video, Sakurai expresses that Sephiroth is one of the most iconic boss characters which makes him deserving of special treatment. Players are giving Sephiroth some sort of special treatment, but it's in the form of a competition to see who can embarrass this iconic villain the fastest.
In all fairness, the techniques that players are using ride a lot of luck over skill. Mr. Game & Watch's hammer isn't guaranteed to strike a 9 every time, and Sephiroth could counter or shield whenever the attack is used. Some of these runs are taking players hundreds of attempts. While each one only takes a handful of seconds, resetting over and over can be mentally taxing. Regardless, it is hilarious to see a character who was able to slice Galeem in half be taken down in less than 3 seconds.
Sources: Ross O'Donovan, Hungrybox