When Shiraishi goes to meet with "the ghost" of his deceased girlfriend, his head balloon captures his neck into the noose and hangs him. Shortly after Shiraishi joins Terumi in death, more head balloons start to appear, and even begin chasing people down to claim their lives.

Shiraishi is there, on top of a tree, and attempting to get her down. However, a noose inexplicably shows up and he ends up hanging myself, his head suddenly ballooning to the same size as Terumi’s.

The balloon of Shiraishi drags the hanging corpse of Shiraishi as the balloons of Terumi and Shiraishi share a kiss while floating. In the manga, Kazuko rushes to the police station to inform them about the happenings; however, when the police arrive on her account, they see nothing.

Just the meaning of what the hanging balloon was in the new Netflix show.

“Hanging Balloon” primarily concerns Kazuko, the friend of a young idol who is found dead, apparently of a suicide by hanging. The celebrity seemingly had no reason to kill herself, so there’s a degree of public interest, including copycat suicides among her young fans.