Tentacle Grimm

The Hydra (unofficial) is an enigmatic type of Grimm found exclusively in the manga.

Appearance
In its base state, the Hydra appears as a small skull-like creature, with three pair of eyes, a pair of horns, and several tentacles. The tentacles can extend longer than usual, possibly to grab targets.

Abilities
The hydra appears to be not quite powerful by itself, and rely mostly on sneak attacks. It can use its tentacles to attack its targets.

The hydra's more omnious ability is to merge a group of King Taijitu into one large Grimm. It also appears to powerup said monsters, making them stronger and more durable.

History
A hydra has been first seen in Chapter 9, as it briefly attacked Roman Torchwick. As Roman noticed the Grimm, he shot it with his weapon and the creature fled.

It then appeared in Chapter 11 observing Team JNPR fighting four King Taijitu. It was briefly spotted by Jaune Arc before fusing with the four serpent Grimm, making them become one large creature.