Anti-Sensei Weapons

The Anti-Sensei Weapons are special weaponry developed for the assassination of Korosensei.

Overview
Anti-Sensei weapons are made with special materials that are effective against only Korosensei and is harmless to humans. So far, they have been shown in the shape of bullets, knives, and clothing/cloth material.

Anti-Sensei Bullets
The Anti-Sensei bullets take the shape of BB gun pellets and are used with have been referred to as airguns which take the appearances of real guns. They break apart Korosensei's cells and are able to be used and conformed in a variety of ways from being able to embed them in something to grounding them up into fine powder.

Anti-Sensei Knives
Green knives that have the strength of ordinary rubber. Like the bullets, they can also be used in a variety of ways  (i.e. cutting them up and pasting them to something).

Other Appearances
The materials used to make the Anti-Sensei weapons have also been used to make cloth and clothing. Shiro's robe is an example of this as well as the nets and sheets that have been used by him.

Trivia

 * The air guns used for the anti-sensei bullets are modeled after M4 Assault Rifles and M1911 Handguns.
 * In the anime, the BB pellets, airguns, and knives have the acronym S.A.A.U.S.O.(Special Arms Against Unidentified Slimy Octopus) imprinted on them.