Amalgam Skeleton

Amalgamation. This particular skeleton is a powerful hybrid of parts that are mashed together to form a lumbering hulk. However, if commanded, it can use this strange biology alter its form to suit different situations. The skeleton has a number of Evolution Points equal to 5 + half its controller's level (rounded down). It can use EP to augment its body with different evolutions. Its controller can swap one evolution for another as a bonus action, or as many evolutions as they want by using their action.

Evolutions. Below are evolutions the skeleton can use, with their EP cost and effects.

-Increased Darkvision. 1 EP, darkvision increases by 60 ft.
-Blindsight. 2 EP, gain blindsight for 15 ft.
-Extra Legs. 1 EP, gain 2 extra legs. The skeleton speed increases by 10 ft, and it gains advantage on Strength saving throws against forced movement effects.
-Skill Proficiency. 1 EP, gain proficiency in one skill, chosen when you pick this evolution. The skeleton uses your proficiency bonus when calculating their new bonus to that skill. This evolution can be be selected multiple times, but each must be for a different skill.
-Saving Throw Proficiency. 2 EP, gain proficiency is a saving throw, chosen when you pick this evolution. The skeleton uses your proficiency bonus when calculating their new bonus to that skill. This evolution can be be selected multiple times, but each must be for a different skill.
-Natural Armor. 1 EP, increases natural armor, giving a +1 bonus to AC.This evolution can be selected up to 2 times. 
-Increased Damage: 1 EP, the number of damage dice rolled for the spinal longsword and bone missile attacks increase by 1.This evolution can be selected up to 2 times. 
-Extra Attack. 2 EP, gain extra weapon attack when using multiattack. This evolution can be selected up to 2 times. 
-Long Limbs. 2 EP, gain reach on spinal longsword attacks.
-Bone Blast. 2 EP, alters the bone missile attack. This changes it from a ranged weapon attack to a 30 ft. radius cone, and any targets i n that area. must make a DC 17 Dexterity saving throw or take damage equal to the Bone Missile damage, or half as much on a successful save. Once used, this attack cannot be used until 1d4 rounds have passed, and this evolution cannot be changed during that time. 
-Two-Handed Sword. 2 EP, the spinal longsword becomes a spinal greatsword, increasing its damage dice from a d8 to a d12. This evolution cannot be used at the same time as the Shield Proficiency evolution.
-Shield Proficiency. 1 EP, gain proficiency with shields and wield them to gain bonuses to AC. If the skeleton does not have a shield to use, it can create a simple bone shield that functions as a nonmagical steel shield.
-Damage Resistance. 2 EP, gain resistance to one damage type, chosen when you pick this evolution. This evolution can be be selected multiple times, but each must be for a different damage type.
-Damage Immunity. 4 EP, gain immunity to one damage type, chosen when you pick this evolution. This evolution can be be selected multiple times, but each must be for a different damage type.
-Evasion. 3 EP, gain evasion class feature.
-Basic Magic. 2 EP, gain access to 3 cantrips from the sorcerer spell list. The skeleton counts as a spell caster equal to your level, and can cast these cantrips as an action, using your proficiency bonus and Constitution as its spellcasting modifier (spell save DC 17, +9 to hit with spell attacks).
-Advanced Magic. 3 EP, gain 3 first level spell slots, 2 second level spell slots, and 1 third level spell slot. The skeleton can use these slots to cast any spell from the sorcerer spell list. The skeleton must have the Basic Spellcasting evolution in order to use this evolution. Switching to or from this evolution does not restore spell slots; once expended, the skeleton can only restore them from resting for 8 hours.

Bone Missile. Ranged Weapon Attack: +11 to hit, reach 60/240 ft., one target. Hit: 26 (3d10 + 9) magical piercing damage.