Caught up last night - definitely getting heavy Shadow King vibes. Might be a swerve but it seems v plausible that the 'parasite' is the Shadow King trying to use David's power to break through to the real world, and is infecting/partially controlling his memories (i.e. what's happening to Lenny in his head).
Think that episode - if any of what we saw is to be trusted, who even fkn knows with this show - serves as pretty solid indicator that Lock Jaw was right in his assumption: that David didn't know Lenny before the institution, and his mind is now implanting her, either voluntarily or otherwise, into memories that she was not originally a part of. And his current mental perception of her is being twisted by whatever is infecting him. Shadow King using someone he trusted to get him to do things that make him realise his own power.
Fact the dog's name is "King" and never existed might also be a red herring but yeah YOU GUYS ARE PROBABLY ONTO SOMETHING HERE.
PS Kerry/Cary
