Bariyon

Bariyon is a low-class demon classified as kin of Amaimon.

Overview
Bariyon are demons that possess rocks and similar items. Most of the time, they are motionless and make nonsensical sounds. They are harmless for the most part, but what abilities they do have make them useful as punishment tools at True Cross Academy.

Their weight can apparently be neutralized by placing talismans on them.

Appearance
Bariyons appear as simple stones about the size of a football with human faces, often with a strained expression. They appear to be vaguely rounded in most cases. Amaimon is shown to be able to summon much larger, boulder sized Bariyon.

Powers and Abilities
Weight Manipulation: Bariyon get heavier the longer they are held, causing them to weigh down and potentially crush their target. This effect can be applied in opposition to attempts to lift them off someone else.

Extreme Durability: Bariyon are largely resistant to damage, the only known way to destroy them being to incinerate them in intense flame. They can also be destroyed with a Demon Sword, but whether this is considered an "effective" method is unclear.

Independent Motion: Older and stronger Bariyon have the ability to move on their own, launching themselves into the air to come down heavily on a target and pin them to the ground.

Trivia

 * Bariyon seem to take inspiration from two Japanese Yōkai:-
 * The Obariyon is a spirit that jumps on peoples' backs, growing steadily heavier, but if the victim makes it to their destination, the Obariyon becomes gold coins.
 * The Saezuri-Ishi, a boundary stone from Gunma Prefecture that spoke human language.