Appearance

Hydra Squids are giant squid monsters, similar in appearance to Hazers and Inspectors. Their bodies range from a dark green to a dark cyan in coloration. They have three to four tentacles with cyan tips on them. They also have three to five heads on their bodies, with a large cyan eye on each head. If hit, or moved at a rapid speed, their eye will turn red either temporarily, until the player is dead, or until the cycle ends. They are quite large in comparison to the slugcat.

Combat

Hydra Squids are decently quick in water, but not overpowering. If fighting one, make sure to kill every single head, if any are still alive, the Hydra Squid is still able to kill the player. It's most effective to lure them onto land, and put then in a position where they cannot get back to kill them.
Most Hydra Squids will chose to float around the water aimlessly, searching for food such as plants, but if the player choses to hurt them, they will try drowning the player and dragging them to their designated shelter.

Stealth and Evasion

It's quite easy to avoid getting on a hydra squids bad side, as Hydra Squids are generally neutral towards the player by default. If the player throws a rock at them, tries to maul them, or hits them with a spear, they will be angry towards the player for the rest of the cycle.