Dandadan (Manga) Vol 12

A gravely injured Okarun wakes up to an out-of-body experience! And when he answers Momo's phone, he's sucked through the telephone wires to where Seiko and Turbo Granny are in the middle of a battle. Thankfully, Turbo Granny is able to teach Okarun a technique for returning to his body that will also help in the impending alien invasion. Elsewhere, Momo and the others are undergoing their own training, but when they return home on the predicted date of the invasion, they find it's already begun! Viz Media Llc
(W/A) Yukinobu Tatsu