Child Carrying Gang Leader in Field Trip

is chapter 147 of the Beelzebub manga.

Synopsis
Ichirō is asked by a classmate to take role call for the other students accompanying them on the trip, to which he then discovers that the delinquents from Ishiyama High are a part of the trip. Ichirō is surprised by this fact and is even more surprised by how sullen they appear, to which Oga corrects by stating that they're all "super excited". Ichirō then checks up on the other students, as well as Futaba and Mugen (the former wanting to go because of Be'el). He also has a discussion with Aoi about the circumstances regarding their involvement in the field trip and then leaves, but not without giving Oga and the others a warning on not to ruin anyone's time.

The school arrives in Okinawa, where Furuichi describes how different the atmosphere feels. Hilda contradicts by calling the weather 'humid' but Furuichi brushes it off by adding how relaxing it is compared to home, even adding that Alaindelon isn't there. Much to his disdain, however, Alaindelon arrives anyway to supply Furuichi with spare underwear. Meanwhile, Tōjō is a store holding a box of Chinsokō (Okinawan sweet) though is told that everyone is beginning to leave.

At the hotel, everyone (excluding Mugen who had to leave for work) notices that their school name isn't included in the field trip's housing list. Hajime even suggests to write his name on one of them. Before doing so, they notice that another school called Chinhyrō High is included in the trip. Shortly thereafter, students from the said school then enter the hotel where it's revealed that they're also delinquents.

The new delinquents start insulting St. Ishiyama Academy, even spatting on their school's name in the housing list, some students even beginning to harass the female students. Ichirō and Sakaki come to defend their school, even starting to use force, but are quickly outnumbered by the other students. One student tries to punch Ichirō but Oga gets in the way; Oga then retaliated by brutally punching the attacker (claiming that the punch "hurt"). Tōjō and Himekawa also attack the other delinquents for their own reasons (one stepped on Tōjō's Chinsokō and another provoked Himekawa).

As the rival delinquents are awed by the strength of Oga, Tōjō, and Himekawa, a fellow delinquent carrying a baby on his back enters the building and complains that there's a noisy racket. A hotel staff member clarifies the delinquent as being the "child-rearing badass" that she'd been hearing about.