The Brainstorm skin is an Rare Fortnite outfit. Brainstorm was available via the Item Shop for 1200 V-Bucks and you can buy it from Fortnite Item Shop when it will listed.
Fortnite Brainstorm Outfit Details
This one's a thinker.
Fortnite Brainstorm Outfit PNG Images
Here is the PNG images of Brainstorm below!