Shorty Alien's Mission was the scariest arc in Gantz (imo)

What makes this arc special to me is that: 1) This was the first time an alien invaded the protagonist's life (even before vampires). 2) This is the first and only time Kurono had to complete a mission completely alone. 3) Due to the fact that Shorty Alien uses telepathy to communicate with the victim, it creates the feeling that he is a creepy "all-seeing" being who can easily drive you crazy. At the same time, since we understand what motivated his actions, we know that he will not stop until he kills all the people close to Kurono. 4) The last look that Shorty Alien gives Kurono makes me feel both sorry and anxious. I felt bad for Shorty Alien bc he lost all his brothers, and his revenge wasn't unreasonable. But I was worried, because at the first time of reading the arc, I didn't know if some Shorty Alien's were still somewhere ready for tracking Kurono. And later, when Izumi deceives Kurono, he tells him exactly about Shorty Alien. I think the memories of that mission haunted Kurono in nightmares for a long time.