The Marshmello skin is an Epic Fortnite outfit. Marshmello was available via the Item Shop for 1500 V-Bucks and you can buy it from Fortnite Item Shop when it will listed.
Fortnite Marshmello Skin Details
Start the party. Reactive: Lights up while using musical emotes.
Fortnite Marshmello Skin PNG Images
Here is the PNG images of Marshmello below!