Hagonizer (5e Creature)
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Medium monstrosity, unaligned
Amphibious. The hagonizer can breathe air and water.
Elastic Limbs. The hagonizer has advantage on ability checks and saving throws made to escape a grapple and it can pass through spaces as small as 2 by 2 feet without squeezing and spaces as narrow as 2 inches wide by squeezing.
Slime Armor. On land, the hagonizer's mucus forms a protective barrier. The hagonizer gains a +2 bonus to its AC and resistance to acid, fire, lightning and poison damage.
Suffocating Ooze. In water, the hagonizer's mucus swells to form a sticky cloud. A 15-foot cube centered on the hagonizer becomes lightly obscured and requires a successful DC 12 Strength (Athletics) check to swim through; creatures make this throw when they first enter the area or if they start their turn there, and a success lasts until the creature leaves. The hagonizer ignores these effects.
Rasp. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 13 (2d10 + 2) slashing damage.
Bodily Invasion. The hagonizer attempts to enter the body of a Medium or larger creature within 5 feet of it. The target must succeed on a DC 12 Strength saving throw or take 20 (4d8 + 2) bludgeoning damage as the hagonizer crawls inside; Medium creatures make this throw with advantage, while creatures which have been hit with its rasp attack in the last round have disadvantage. While inside a creature, the hagonizer has total cover, can only target that creature and its attacks automatically hit, and it takes half the damage the creature takes whenever it is damaged; the creature it is inside takes 18 (4d8) bludgeoning damage at the start of its turn. If the hagonizer takes more than 25 damage in a single turn, it immediately exits the creature, using all of its movement for its next turn but dealing 14 (3d8 + 1) damage to the creature in the process.
Similar to the less threatening hagfish, the hagonizer mainly feeds on carrion and scraps; unlike the hagfish, it is more than willing to attack humanoid prey to gain access to them when hungry. With very little hard tissue in its body, possessing only a simple skull and a cartilaginous spine, the hagonizer easily slips through tiny cracks and prefers to feed from the inside of larger corpses out. If threatened, it releases incredible quantities of mucus from pores along its body; this unique organic substance balloons explosively in water to form an impassable sludge, an environment the hagonizer is perfectly suited to.
Vampire Spawn. While its origins are unknown, the hagonizer species shows no traces of being magically created despite its unusual nature, and it is theorized by some historians that they were intentionally bred by a vampire over the course of centuries. This conjecture is supported by a long-documented history of these creatures being employed to guard the lairs of certain vampires, whether by infesting a moat or gathering around a hidden underwater entrance. In this role, they not only serve as security but as living waste disposal, thriving off of drained and discarded corpses given to them by their master. In any case, they are noted for being easy to charm, hypnotize, and otherwise manipulate, to the point where some unscrupulous but mundane pirates have been known to keep several hagonizer as pets.