Araark

Multi Colour Scales. When the aark rolls for initiative and at the start of its turn, roll a d8, the aark gains vulnerability to that damage type and resistance to all other damage types except radiant, necrotic and piercing, slashing and bludgeoning from magical attacks. This is reflected in the colour of the scales changing. The damage type of the aark's Swipe and Spit attacks also changes depending on the current Multi Colour Scale. 

1. Fire, bludgeoning
2. Cold, bludgeoning
3. Poison
4. Acid, piercing
5. Lightning, piercing
6. Thunder
7. Force, slashing
8. Psychic, slashing

Ranged Opportunity Attack. The aark uses its Scale Shot attack for opportunity attacks. Its range for when to make an opportunity attack is 10 ft. so a creature must move outside of that to provoke one. 

Swipe. Melee Weapon Attack: +5 to hit, reach 10 ft., every target within 10 ft.. Hit: 17 (3d10 + 1) damage. 

Scale Shot. Ranged Weapon Attack: +5 to hit, range 60/100 ft., 1 target. Hit: 10 (2d8 + 1) damage. 

Ostentatious Shine: As a bonus action, the aark can shine its scales and attempt to blind every creature within 5 feet. The creature must succeed on a DC 15 Dexterity saving throw or be blinded until the end of the aark's next turn. 

Retaliation Roll: When the aark is hit with an attack it can use its reaction to roll up in a ball and move up to 30 ft. as well as gaining a +5 to AC. If it moves through a creatures space, that creature must succeed on a DC 14 Dexterity saving throw or be knocked prone. 

Clay Pigeon: If the aark misses a creature it can see with its Swipe attack it can use its reaction to attack that creature with a Scale Shot attack.