The doctor is flanked by two Bubblehead Nurse expies, whose bodies bend backward unnaturally and their idle animation have them violently twitch and spasm before you make your first move. Enough motivation to kill them fast just so they stop being creepy.
Of course the doctor himself is nothing short of nightmarish. He looks like an obese doctor with giant pliers for a weapon, there are visible bloodstains on his costume and his head looks deformed and his face looks like some one tore off a baby's face and then sewed it on some one's head.
It gets even worse if you take into account that Mitsuru may have been experimented on by the scientists under the employ of "Granddaddy Dearest", which may explain her reaction to the Shadows in question.
Really, the entire third stratum. You think the first haunted school half is not that bad? The place is still full of F.O.Es that looks like baby with bloody bag on its head chasing after the party, disembodied piano playing Für Elise in background that you have to get closer to shrug off said baby, and the "Six Sisters" scenario where the party step inside a room, the light suddenly goes off, and disembodied giggles come from everywhere before the light is on again. Watch the minimap on the lower screen, and you then realize you've been surrounded by six F.O.Es the entire time the light was off. The second hospital half has several arms hanging from the ceiling as a background environment, bloody handprints appearing on the ground and squelching noises as warning signs of the F.O.Es' domain, and there's a part where Rei has to go through those things alone so the party can advance.
Whomever hears the bell to the end will die. What do you hear throughout the trailers? The bell.
Any F.O.E. that looks like a baby riding a horse, like the all-gold example encountered by the hosts of Persona Stalker Club. To think that something that cute could be a Demonic Spider.
The design for the boss of the fourth stratum: A Dear Friend/Shadow Rei, which turns out to be a Hair-Raising Hare. Jesus Christ…
Everything about the fourth stratum boss is nightmare fuel. Compares to other Shadow Selves, Shadow Rei is notably bestial after goes berserk; roaring, screeching monstrosity who can't even speak a coherent word and literally drools at prospect of killing its real self. Even before going berserk, Shadow Rei is a bundle of helplessness that came from her despair, suicidal thought and nihilsm for having no self-worth. Small wonder that Erebus exists and immortal; if one girl can form this horrible a death wish, imagine that of all of humanity.
TheReaper is back, as an F.O.E. for the final dungeon.
The revelation what would happen to every one if the two teams don't just leave the Labyrinth after the Fourth Stratum. Basically, Chronos will absorb Zen into himself to become a whole, and then erase the Labyrinth with every one inside it, which would not just result in everyone dying, but everyone being erased from the timeline for good!