Submitted by Jeremy
Morgan (Anya Taylor-Joy) was created in a lab and managed to grow rapidly and develop super intelligence, strength, and agility, but her prolonged containment inside the facility has caused her to have negative emotions, leading to violent tendencies.
Morgan kills just about everyone except for Lee (Kate Mara), Skip (Boyd Holbrook), and Amy (Rose Leslie). Amy brings Morgan to the lake that she promised to take her to, only for Lee to show up and drown Morgan in the lake, right before getting rid of Amy and Skip.
Morgan is declared a failure, and the ending suggests that Lee is also a synthetic life form, but she’s deemed “perfect” for not ever having developed emotions and being able to perform basic functions as a result.