It concerns two skins. First of all, there’s Ripley, the main character from the first four Alien movies. She carries her cat Jonesy with her. Second, there is the Xenomorph, or the titular alien.
In addition to the skins, there is also a Power Loader Arm pickaxe, a glider based on a CHeyenne Dropship and an emote called Burst Case scenario, which just like in the movies an alien bursts through the character’s rib cage.
Fortnite has been full of crossovers with other franchises in recent years, from Marvel and Terminator to Batman and Street Fighter.