Bone amalgamation

Necrotic Resurrection. If destroyed, the Bone amalgamation reforms in 1d100 days if it has not been blessed, reviving with all its Hit Points. The new body appears in an unoccupied space anywhere else in a 200 foot radius. revives as a regular Skeleton Skeleton and has to rebuild itself into a Bone amalgamation

Multiattack. The Bone amalgamation makes three attacks, using Eldritch Burst or Paralyzing Touch in any combination.

Mimicry. After Seeing a attack, spell, or action made, it can memorize the exact requirements to make said action [roll]1d20[/roll] and utilize it later in a attack or action for itself [roll]1d20[/roll]+each time used.

Paralyzing Touch. Melee Attack Roll: +12, reach 5 ft. Hit: 15 (3d6 + 5) Cold damage, and the target has the Paralyzed condition until the start of the lich’s next turn.

Spellcasting. The Bone amalgamation casts one of the following spells, using Intelligence as the spellcasting ability (spell save DC 20):

At Will: any spells collected by corpses
2/Day Each: Animate Dead, Dimension Door, Plane Shift

Protective Magic. The Bone amalgamation casts [Tooltip Not Found] or Shield in response to the spell’s trigger, using the same spellcasting ability as Spellcasting.

Legendary Action Uses: 3. Immediately after another creature’s turn, the bone amalgamation can expend a use to take one of the following actions. The bone amalgamation regains all expended uses at the start of each of its turns.

Disrupt Life. Constitution Saving Throw: DC 20, each creature that isn’t an Undead in a 20-foot Emanation originating from the Bone amalgamation. Failure: 31 (9d6) Necrotic damage. Success: Half damage. Failure or Success: The Bone amalgamation can’t take this action again until the start of its next turn.

Rebuild. If damaged, can take a turn to rebuild itself with and nearby skeletons. [roll]1d12[/roll] self healing