|Spoiler Alert: This page contains spoilers. Read at your own risk.|
Mahouka Koukou no Rettousei Yonkoma Hen (魔法科高校の劣等生 よんこま編) is a spin-off comedy manga of the Irregular at Magic Highschool. The adaptation is by tamago. It is published by Kadokawa and in serialized in Dengeki Comics NEXT, and has been serialising since April 2014.
The Yonkoma Arc is a non-canon comedy spin-off of the main series done in a standard 2x4 hybrid comic format, also known as 4-koma style. The arc covers a number of events form the main series as well as unrelated shorts, but in an exaggerated comical fashion.
Volume three covers the Visitor Arc.
Volume five covers the Ancient City Insurrection Arc.