While we sort of already know what to expect from amiibo functionality in Nintendo Switch games nowadays, it's always nice to know exactly what will happen when they're scanned in a certain game.
In the case of Super Mario 3D World + Bowser's Fury, it's a game divided into two different adventures.
To use an amiibo in Super Mario 3D World, you need to bring up a little amiibo symbol and then scan your figure in. Here's the full explanation, courtesy of Destructoid:
"Using amiibo in Mario 3D World portion is very straight-forward: you hold left on the d-pad while playing to bring up the amiibo symbol prompt when in a level, then scan. 99% of figures create random power-ups or a 1UP mushroom."
As already stated on the official game site, Cat Mario summons an invincible White Cat suit, and Cat Peach can create randomised power-ups - but seemingly has no "special" functionality.
In the new add-on adventure Bowser's Fury, the "two main figures" for this mode are Bowser and Bowser Jr, and "everything else will summon random power-ups". Once again, you hold left on the D-Pad to scan in figures. Here's the source's full rundown:
"Using Bowser on the amiibo NFC point will immediately wake Fury Bowser from his slumber. While this is normally a hazard that needs to be managed and avoided, calling upon Bowser does have its perks, as certain walls/obstacles can only be destroyed by Fury Bowser's abilities. So if you need him to immediately appear to enter a specific area, you don't have to wait for him. We did test multiple Bowser amiibo, and figures like wedding Bowser will also perform the same functionality."
"Bowser Jr. is special too, allowing you to unleash an explosion of sorts. You can't spam it as it has a cooldown: there's not much more to it!"
It's worth noting the Bowser and Bowser Jr. amiibo are not classed as unique/special in Super Mario 3D World.
So, there you go - that's how amiibo functionality works in Super Mario 3D World + Bowser's Fury. If you would like to learn even more about the game, be sure to check out our own preview.