Battle, befriend, or become more than 100 bizarre alien life forms in this all-new creature collection for the Starfinder Roleplaying Game! On countless worlds orbiting countless stars, strange and wonderful creatures await discovery. In this book, you'll find rules and background information about creatures ranging from undead androids and robot dragons to deadly laser-spined flowers and mysterious sea skeletons. Many species include rules for making your own playable alien character, from beings made of coral to animals uplifted by sapient fungus to creatures truly bizarre to behold. You'll also find plenty of new equipment and player options, including a new set of augmentations that allows your character to adopt the strange features of dozens of existing playable alien species. Explore the extraordinary with Starfinder Alien Archive 4! Inside this book, you'll find the following: -Nearly 100 uncanny life-forms both classic and new, from the batlike grioth and horrifying brain collector to the vengeful endling and dreaded plasmalisk. -A dozen races with full player rules, letting you play everything from a fungus-uplifted animal to a humanoid made of magical coral. -New alien technology to help give your character an edge, including armor, weapons, magic items, and more. -New rules for grafting the strange physical traits of other species onto your own character, creating a staggering array of customization options!