Enigma Boy, Part 5 (エニグマの少年 その⑤ Eniguma no Shōnen Sono 5), originally I Have to Open It! (開けるしかない！ Akeru shika Nai!) in the WSJ release, is the one hundred forty-third chapter of Diamond is Unbreakable and the four hundred eighth chapter of the JoJo's Bizarre Adventure manga.
Terunosuke tells Yuya that he made a bad decision going against him, as he would also be going against Kira's father. Yuya (talking through Highway Star) says to quit stalling and demands Terunosuke to hand over Koichi's paper. Terunosuke slams the door on Highway Star, which separates its body into multiple feet and chases after the taxi.
Suddenly, the taxi stops and Yuya notices that it's parked on the side of the road. Highway Star inspects the vehicle and notices Terunosuke's scent is all over it, but Yuya doesn't see anyone inside. Highway Star discovers a paper inside with Josuke and Koichi's scent and is about to impulsively open the car door, but Yuya stops his Stand, knowing that the paper is a trap.
Yuya looks inside the car and finds a paper stuck in the top of the door. Highway Star opens it up and quickly extinguishes the fire that comes out of the paper, while Yuya is surprised that the enemy can even trap fire in his Stand. When trying to open Josuke and Koichi's papers, scorpions pop out.
The paper opens further to reveal a chemical which tears holes through the paper due to its acidity. After sniffing, Yuya smells something metallic inside. He almost touches his chin out of fear, but snaps out of it and unfolds the paper since he has no choice, awaiting what pops out of the paper next to attack him.