Some of the monsters have tentacles that appear phallic.

Two young people embrace each other whilst naked but, no genitals can be seen.

A girl's bare breasts can be seen in one scene.

A teacher's bra and knickers can be seen in one scene.

The violence is largely bloodless but, quite disturbing.

One boy has his nose broken by a bully, blood can be seen.

Monsters penetrate people with their tentacles causing them to mutate into giant blobs.

A character uses a sword to cut monsters - no blood is shown.

A teacher is tackled to the ground violently.

Some mild language such as: asshole, bitch, shit etc

One character is seen smoking a cigarette.

This anime is notorious for been too gross.

Some of the monsters could be frightening to some people.