Chameleos

Chameleon Skin. As a bonus action on each of its turns, the chameleos can become invisible. This invisibility can only be shut off when the chameleos attacks or is hit with fire damage. 

Silent Movement. The chameleos has advantage on Stealth checks made to hide. If the chameleos is invisible, the roll is treated as a 20, regardless of the number rolled. The chameleos flies and walks silently and leaves no footprints when moving. 

Independent Eye Movement. The chameleos can see in all directions. It also has advantage on Perception checks based on sight. It can also see through effects that cause an area to be lightly or heavily obscured.  

Potent Venom. If the chameleos poisons a creature, it takes 12 (2d10) poison damage at the start of each of its turns until it is cured. 

Legendary Resistance (3/day). If the chameleos fails a saving throw, it can choose to succeed instead. 

Magic Weapons. The chameleos's weapon attacks are considered magical. 

Magic Resistance. The chameleos has advantage on saving throws against spells and other magical effects.  

Multiattack. The chameleos makes three attacks, one with its bite or tongue and two with its claws, or it can make two Poison Glob attacks.  

Bite. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 22 (2d12 + 6) piercing damage plus 6 (1d10) poison damage. 

Tongue. Ranged Weapon Attack: +15 to hit, range 10/45 ft., one target. Hit: 18 (2d10 + 6) bludgeoning damage, and the target must make a DC 22 DEX Save. If the target fails the save, the chameleos can choose to either take its weapon or render it grappled (escape DC 19). The chameleos can pull a grappled target up to 30 ft. closer to it on each of its turns automatically, and can make an additional bite attack as a bonus action. It can only grapple one target at a time, and cannot use this attack while grappling a creature. 

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 6) slashing damage. 

Poison Glob. Ranged Weapon Attack: +15 to hit, range 15/60 ft., one target. Hit: 22 (4d10) poison damage, and the target must make a DC 22 CON Save or it is poisoned for 8 hours. A creature can repeat the save at the end of each of its turns, ending the effect on itself on a success.   

Toxic Cloud (Recharge 6). The chameleos sprays venom in a cloud in a 45 ft. radius sphere centered on itself. Each creature that is inside the cloud when it is created or starts its turn there must make a DC 22 CON Save or it takes 84 (16d10) poison damage on a failed save, or half as much on a success. A creature that fails this saving throw is also poisoned for 8 hours. The cloud remains for 1 hour. A strong gust of wind will move the cloud up to 30 ft., but will not disperse it. 

The chameleos can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The chameleos regains spent legendary actions at the start of its turn.

Swat. The chameleos makes a claw attack. 

Hide in Plain Sight. The chameleos turns invisible and moves up to its speed, walking or flying. 

Spit Venom (Costs 2 actions). The chameleos uses its Poison Glob attack on two different targets. 

Enrage (Costs 3 actions). The chameleos becomes enraged, and gains the following benefits for its next 3 turns:

1. Fog fills the area within 1/2 mile of the chameleos, centered on it. The area is then heavily obscured. The chameleos has advantage on any attack on an enemy within the fog. The fog does not travel with the Chameleos, and can be blown away by a strong wind.
2. The chameleos can make an extra Poison Glob attack on its turns when it uses it twice, and its Spit Venom legendary action attacks 3 times. 
3. The chameleos adds an additional 6 (1d10) poison damage to all of its attacks except Toxic Cloud. 

The chameleos loses these benefits at the end of its third turn. It then cannot make this legendary action again for another 3 turns.