Anub'arak

Scarab Armor.  Anub'araks shell shines like a finely polished opalescent shield. Anub'araks wings are hard as bone.  It's starting AC is 23.  Each time it is hit, a shell is removed and its AC is reduced by 3.  It is also immune to all damage types until its first shell is broken off.  For each shell removed, up to 3, it becomes less resistant. Magic missle and AoE does not remove shells.

• 1st Shell: AC 23, Immune to all damage.
• 2nd Shell: AC 20, Resistant to all damage.
• 3rd Shell: AC 17, No resistances.
• No Shell: All damage types do double damage.

Scarab Host. Anub'arak's wings flutter as its whole body vibrates. At the top of Anub'arak's turn, it sheds a swarm of scarabs to fight for it.  The swarm of scarabs have the following traits:

• AC 12
• HP 22
• Speed 20 ft.
• Resistances. Physical Damage
• Bite. Melee Attack +8 to hit, reach 5 ft., one target. Hit: (2d4) piercing damage or (1d4) if its health is reduced.

Legendary Recharge. Anub'arak rolls a 1d6 at the start of its turn.  It can choose to recharge one ability, if it passes that abilities recharge number.

Max HP. DM can boost its health to 245.

Multiattack. Anub'arak can make three attacks: one with its bite and two with its claws.

Claw. Melee Attack: +8 to hit, reach 10 ft., one target. Hit: (3d4) slashing damage and the target is grappled.  The grappled creature makes an escape save, DC 13 Dexterity, at the beginning of their turn.  It can only grapple one creature at a time.

Bite. Melee Attack: +8 to hit, reach 5 ft., one creature grappled by it.  Hit: (4d4) piercing damage.

Anub'arak may choose 1 of the following bonus actions:

• Impale (Recharge 3-6). A line of spikes travel through the ground, sounding like a knives being sharpened Each creature in a 30-ft. line that is 5 ft. wide must make a DC 17 Dexterity saving throw, taking (3d4) slashing damage and become stunned until the end of their turn on a failed save, or half as much damage and avoids being stunned on a successful one.
• Burrow Charge (Recharge 3-6). It burrows through the ground up to 20 ft. Each creature within 5 ft. of where it immerged, must make a DC 17 Dexterity saving throw, taking (3d4) bludgeoning damage and is knocked prone on a failed save, or half as much damage and avoids being knocked prone on a successful one.

Harden Carapace(Recharge 4-6). Anub'arak retreats into its shell making it appear as if it is one giant opal stone.  Until the start of its next turn or after it uses any legendary action, it has a +5 bonus to AC, and it takes no damage from magic missile.  It cannot take this reaction after it loses its shell, even though it may try.

Anub'arak 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. It regains spent legendary actions at the start of its turn.

Cocoon (Costs 3 Actions, Recharge on 6 only). It spits out a thick silk, wrapping a creature within 30 ft. The creature must make a DC 17 Dexterity saving throw.  On a failed save, the player becomes encased in a full cocoon, and is paralyzed and suffocating until the cocoon is half removed.  On a successful save, the player is wrapped in a half cocoon and becomes grappled.  It takes 1 action to reduce the full cocoon to a half cocoon, and 1 action to remove the half cocoon.

(A creature can hold its breath for a number of minutes equal to 1 + its Constitution modifier (minimum of 30 seconds)).

Bonus Action (Costs 2 Actions).

One Attack Action (Costs 1 Action).

Roll For Recharge (Costs 1 Action).

Locust Swarm. Once it loses its second shell, the scarabs under its wings begin to swarm.  Any creature starting their turn within 5 ft. of it takes (2d4) piercing damage.