Super Mario Maker 2 has all kinds of tools players can use to craft their own Mario worlds, but there's at least one power-up you'll find that people may not be as familiar with. It's called the "Superball Flower" and it comes from Super Mario Land, the Game Boy game that was released back in 1989. The power-up is one players might miss if they're more into building and not so much into completing the story mode, but having it in the game means player should be able to come up with some interesting puzzles in their levels.
The Superball Flower functions similarly to a normal Fire Flower in that you can toss projectiles out that'll bounce around, but they move quite a bit differently. Instead of bouncing forward for a while, they ricochet around until they hit something. It also changes the music that's playing for those who wield it which you can see in the video below which is one of many examples that people have shared after discovering the Easter egg.
Although it’s likely common fact, the super ball flower from Super Mario Land appears in Super Mario Maker 2 AND the Birabuto Kingdom Theme plays when you have it. A late, yet welcome celebration for both Daisy’s debut and Mario Land overall! pic.twitter.com/9b9R0udmdN— Diego Alex (@LyazidSantiago) June 27, 2019
To add the Superball Flower to your toolbox, you'll need to take a break from constructing levels and attempting others to play the story mode. As you progress through the mode, you'll get some jobs from Purple Toad, one of which is called "Spiny Shell Smashers." Just complete this job and you'll find that you then have access to the Powerball Flower.
As more people unlock the power-up, you'll probably start seeing it in other players' online builds soon enough, so it's probably best to familiarize yourself with it and start practicing your angles. The example below that one player shared showed how you can use the power-up to reach areas that wouldn't normally be accessible to Mario with the power-ups he's accustomed to. By the time you progress through the story mode and return to the game's online component, you should be equipped to take on all sorts of challenges other players might come up with.
Super Mario Maker 2 is now available for the Nintendo Switch.