Mii Gunner
One of the fighters in the Super Smash Bros. franchise. They were introduced in the SSB4 and have returned in Ultimate along with their friends the Mii Brawler and the Mii Swordfighter.

In all of the games it appears in, Mii Gunner is typically considered a low-tier by competitive Smash players, but it can be hilarious to see these online because of how bizarre they can look.
The amount of Mii Gunner mains has risen by a lot in the last few days because a costume of Sans from Undertale can now be purchased for the Mii Gunner.