Eris Can't Actually Look at Anything
Eris can't actually look at anything because of the way Eris's eyes don't track in her head. Eris's pupils don't move with Eris's eye sockets, they're separate and Eris's eye sockets are as blank as they appear to be. Eris's lips aren't connected to Eris's brain, Eris can't feel anything except joy in them but the muscle's motions are still the right ones to give the wrong impression, and they work perfectly in a way that only Eris knows how to use. They smile like nothing is wrong but Madison can hear the joy and the horror all mixed up and there's something about the smile that makes Madison realize there's nothing wrong because everything is wrong.