|Spoiler Alert: This page contains spoilers. Read at your own risk.|
|Active Air Mine|
|Area of Effect|
Active Air Mine (能動 空中 機雷) is a spell specifically made for the Newcomers Speed Shooting event that Shizuku participated in. The spell was developed for the event by Tatsuya in conjunction with Shizuku, and after the event it was entered into the index (by Tatsuya's request, he was not listed as the developer, but suggested Shizuku instead).
It enables the user to tag all solids that enter the Magic Activation Zone with magic vibratory waves, destroying the targets. By generating compression waves inside the target, it undergoes repeated partial expansion and contraction. The rapid heating and cooling is repeated and hence, even solid rock weakens and collapses.
This magic sets numerous epicenters within the area where the targets are present, which generate virtual waves that give rise to vibratory waves within the targets. Instead of directly applying the waves to the targets with magic, the user sets up an area which causes the phenomena of applying such waves to the targets. The moment the waves from the epicenter come into contact with such a target, the virtual waves become real waves within the target and affect it in reality. 
The Activation Sequence sets a cube within the target area which is 10 meters on each side, with the vertices and the center, nine points in total, being designated as epicenters.
The spell is capable to work efficiently only because the static environment it is used in. There is no need to enter variable coordinates separately each time, but instead, the user can simply input into the Activation Sequence numbers they desire, and instantly invoke the magic. This magic doesn't require changes in duration or power either.
However, Watanabe Mari instantly seen the tactical potential the magic may have. If controlled properly, it could serve as an active shield.
Active Air Mine's developer remained unknown because Tatsuya wanted to avoid being conspicuous and Shizuku who refused to take credit for the development. Even after that, the Magic University continued to approach Tatsuya, and finally Tatsuya responded to the persuasion because there was no reason for refuse after becoming an official member of the Yotsuba family, and it was officially recorded in January 2097.
On May 2, 2097 Active Air Mine was modified into a tactical-grade magic by EAND who are rebels from the west Guinea Bay area. People caught in the vibration area of this magic will be crushed until their entire bodies break and all that is left is a deadly blood box.
The targeting is done by the aiming assistance of the CAD, so the user only needs to aim the CAD forward and pull the trigger. However, since the activation formula is long, the operator is required to have suitable calculation speed. The only known user is Mensah Aufa.