Retro Sci-Fi is a Rare Fortnite Contrail. Retro Sci-Fi was available via the Battle Pass during Season 4 and could be unlocked at Tier 20.
How-to Get the Retro Sci-Fi Contrail
Retro Sci-Fi is part of Season 4. If that season is still currently in the game, you can obtain this item by purchasing and/or leveling up your Battle Pass.