Anti-Sensei Weapons

Every anti-sensei armament is shaped from a special rubber-like compound that reacts only with creatures built from antimatter tentacles, Korosensei chief among them, which leaves the material completely safe for ordinary people to handle. Over the story it turns up as BB rounds, grenades, knives, nets, cages, and woven cloth.

The distinction matters because tentacle beings shrug off conventional arms entirely. Metal blades and bullets simply melt when driven through their bodies. The rubbery weapons work the opposite way, causing a tentacle lifeform's cellular tissue to rot away the instant it makes contact.

The pellet variant consists of small spherical BBs launched from compressed-air guns disguised as genuine firearms. Users get creative with them, tucking a round inside a baseball for a delivery far quieter than the gun, or scattering them underfoot so the target's tentacle feet decay on a misstep. Terasaka once packed them into a fragmentation grenade for an early attempt on the octopus. The knife version resembles green military combat blades with the flex and give of rubber, and it lends itself to trickery: slices can be taped to a palm before a handshake, planted as spikes in a pitfall, or bound to bamboo poles as makeshift spears. The same substance can be spun into fabric, yielding protective clothing that dissolves any tentacle flesh brushing against it, along with nets made from the fibers.

The technology also scaled up to enormous proportions during Operation Last Assassin. The Spear of Heaven, a tortoise-shaped satellite formally called the Anti-Tentacle-Creature Permeable Laser Satellite, fired a silent beam tuned to vaporize tentacle beings, its power drawn from antimatter lifeforms and boosted by a giant particle accelerator while it hung 400 kilometers above Japan. Its first shot ran at only a fifth of full strength and narrowly missed. To pen Korosensei in during the week-long recharge, the government raised the Shield of Earth, a domed barrier formed when six converging lasers built a hexagonal shell that morphed into an anti-tentacle enclosure, later crippling Yanagisawa when he was hurled against it.

Class 3-E relies on the pellets, blades, and textiles throughout its campaign against Korosensei, with Terasaka improvising the grenade and Karma wielding an anti-sensei butterfly knife in the third episode. Chiba handles a sniper variant in the anime. The large-scale hardware, the Spear of Heaven and the Shield of Earth, belongs to the government forces coordinated through Karasuma. A few quirks round out the arsenal: the material can be touched indirectly through something like tissue paper, the air guns are modeled on M4 rifles and M1911 handguns, and in the anime the gear is stamped with the acronym S.A.A.U.S.O., short for Special Arms Against Unidentified Slimy Octopus.