This is the Royal Crest from the Legend of Zelda series, recreated as a custom stage for Super Smash Bros. Wii U, by Kotaku reader JakeJakeThePillowSnake. So cool! Check out more awesome custom stages in our ongoing roundup
https://kotaku.com/the-coolest-custom-stages-for-super-smash-bros-wii-u-1667381436
Also, for a point of comparison, here’s an illustration of the Royal Crest from the Zelda wiki page on the topic:
