Asterzias

Amphibious. The asterzias can breath both air and water.

Bouncing Doom. The asterzias cannot crawl more than 5 feet per round in normal conditions. Instead, once per round it can bounce from one point to another for up to 20 feet.

Environment Meld. While the asterzias remains motionless, it shifts the pigments on its skin to match the surroundings and becomes indistinguishable from rock formations or small bumps of the same material it is attached to.

 Oozing Body. Beneath the skin layer, the internal biology of the asterzias just consists of venomous ooze leaking from its tiny suckers. When attached to a creature, at the start of the asterzias' turn the creature takes 3 (1d6) poison damage. Carefully squeezing a dead asterzias, can fill a small vial of poison that can coat a weapon using an action. The poison remains for 1 minute or until an attack using this weapon successfuly hits and poisons a creature.  A creature hit by an asterzias’ venom coated weapon must make a DC 13 Constitution saving throw or take an extra 2d6 poison damage.

Spider Climb. The asterzias can attach itself to difficult surfaces thanks to its suction cups, including upside down on ceilings, without needing to make an ability check.

Crush. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 6 (1d6 + 3) bludgeoning damage.

On a successful attack, the asterzias attaches to the target. While attached to the target, the asterzias can attack no other creature except the target but has advantage on its attack rolls. The asterzias's speed also becomes 0, it can't benefit from any bonus to its speed, and it moves with the target.

A creature can detach the asterzias by making a successful DC 13 Strength check as an action. On its turn, the asterzias can detach itself from the target by using its Movement action.

Venomous Aura(1/Day).  When not attached to creatures, a 5-­foot radius of poisonous fumes extend out from the asterzias and moves with it. Any creature caught in the magical aura at the start of its turn, must succeed on a DC 13 Constitution saving throw or become poisoned and take1d6 of poison damage.

If a creature's saving throw is successful, the creature is immune to this creature's Venomous Aura for the next 24 hours. The aura lasts as long as the asterzias maintains concentration, up to 10 minutes (as if concentrating on a spell).