Diamond is Unbreakable - Chapter 91 
Sheer Heart Attack, Part 3 (シアーハートアタック その③ Shiā Hāto Atakku Sono 3), originally Powerful Even Through Remote Control! (遠隔操作でもパワフル！ Enkaku Sōsa de mo Pawafuru!) in the WSJ release, is the ninety-first chapter of Diamond is Unbreakable and the three hundred fifty-sixth chapter of the JoJo's Bizarre Adventure manga.
Kira, still hidden behind the door, claims that his Killer Queen's Sheer Heart Attack is invincible. Meanwhile, Jotaro and Koichi see the seemingly indestructible miniature tank rushing to attack with concern. Star Platinum pummels it away, but Sheer Heart Attack is relentless, rushing toward them again. Jotaro tells Koichi to stay away, trying to break Sheer Heart Attack by splitting it, but Star Platinum isn't fast enough and throws it away before the tank explodes, slightly wounding Jotaro and destroying the front of the shoe store.
As Sheer Heart Attack goes back up again, Koichi yells at Jotaro that it's power indicates that the user is nearby and that he is now defenseless. He proposes to use Echoes to scout for the killer, but Jotaro tells him to only protect himself, saying that the Stand is independent. Koichi doesn't believe it and sends Echoes to look around, spotting Kira being already far from the shop. Disturbed at the sight of the killer being this far away, Koichi realizes too late that he is Sheer Heart Attack's target. Jotaro has now figured out that Sheer Heart Attack is a heat-seeking Stand, but is too far away to stop it while Koichi is defenseless, having sent Echoes away.