Stars, Eyes of Heaven / Nightmare Fuel

The Star, Inverted

Due to the fact that Jotaro only remembers the original timeline, and not the events of the new reality, he's functionally missing seventeen years of his life.
Star Platinum verges on Uncanny Valley for Stand users In-Universe, with its moments of oddly autonomous behavior and No Sense of Personal Space to other people. In The Star, Inverted, Polnareff catches it visibly clipping in its movement. In Demolition Man, the Stand's largely expressionless stare is described as predatory.

Tenmei is revealed to suffer sleep paralysis. The readers are given a lovely look of what his episodes are like from his point of view- disoriented, near blind, hallucinating, and paralyzed in excruciating pain, barely able to even recognize anyone as real. The one introduced to the readers also lasts for seven to ten minutes- the average sleep paralysis episode usually only lasts for two.
- From Jotaro's perspective, he wakes up at nearly three in the morning to find Tenmei staring blankly at him, completely unresponsive.
Johnny Joestar makes an appearance- in a wheelchair. After the end of Steel Ball Run in the original timeline, he had learned to walk again using Spin. What happened in between then and now that crippled him all over again?

Jotaro and Tenmei detailing what will happen to Rohan if he doesn't take An Offer You Can't Refuse.
We will watch you. Everywhere you live. Everywhere you go. Everything you do. Everyone you know. If you prove too dangerous, then we will cage you. If you lash out, then we will kill you.
The readers are treated to a sudden Perspective Flip to Kira Yoshikage. The Dissonant Serenity of the lunch date with one of his "girlfriends" was already creepy enough until his thoughts suddenly turn murderous at the drop of a hat, then back to calm.
Jotaro's fight with Kira, if it can even be called that. Throughout the chapter, the stress and blood loss chip away at Jotaro's awareness, speeding up his loosening grip on reality until he finally has a PTSD-fueled breakdown, beating Kira half to death with his bare bloody knuckles.

Remember how Stands and their users have Synchronization of injuries? When Avdol lost his arms to Vanilla Ice, so did Magician's Red. The remains are described as nothing left but something black, charred, bonelike, gnarled.
Polnareff's chapter describes Silver Chariot's transformation into Silver Chariot Requiem.
''Fear bleeding into hollow apathy as armor melted away into faceless shadow.''

When the foundation investigated the human identity of Mikitaka the shapeshifter, they found records of a "Hazekura Mikitaka", but no-one who could actually remember if such a person existed.
EXPANDED ADDENDUM FILE: Kujo, Jotaro is mostly Played for Laughs right up until the last entries, where it warns that an unconscious Doctor Kujo should be approached with extreme caution, otherwise Star Platinum could activate and attack nondescriminately. How exactly did they find that out?
When a Stand user is critically injured, but left alive and untreated, their natural resilience can backfire on them in a very cruel way- by fusing the user and their Stand together.
CONTAINED PERSONS FILE: Weather Report. When not being his usual sweet self, Weather lapses into violent and suicidal BPD, which is already bad- but far, far worse when you remember that this is also a man who could theoretically destroy the atmosphere just by thinking about it. Additionally, due to the self-preservation behavior of his Stand, he cannot be killed.

"Subject must be considered an ongoing threat to the continued existence of civilization, humanity, and life itself."