Rex is a demonic young boy. He appears in "Only Child".
"Only Child"[]
Possessed by some unnamed evil, Rex has taken control of his parents, John and Emily, and regularly abuses his grandmother Desi. He insinuates that she's crazy, grabs her face to force her to smile, and destroys her voodoo shrine to shield against evil. Each time he does this, his parents swoop in to shield him from consequences. This culminates in Rex wanting to do an "apology" presentation about Desi's homeland, Haiti.
In it, he praises Papa Doc Duvalier and taunts Desi over her mother's death at the hands of the Tonton Macoute, revealing that he controls his parents. At this point, Desi realizes that he is possessed and chases him, eventually cornering him and applying her talisman to him in an attempt to purge the evil from him. However, before she can succeed, his parents swoop in once again, this time locking her outside without her inhaler. Rex and his parents then watch Desi suffocate to death from an asthma attack.