Beneficiary Clay Golem

Acid Absorption. Whenever the Beneficiary Clay Golem is subjected to acid damage, it takes no damage and instead regains a number of hit points equal to the acid damage dealt.

Spell Immunity. The Beneficiary Clay Golem is immune to three spells chosen by its creator: immunities include Fireball, Banishment, and Disintegrate.

Immutable Form. The Beneficiary Clay Golem is immune to any spell or effect that would alter its form.

Magic Resistance. The Beneficiary Clay Golem has advantage on saving throws against spells and other magical effects.

Magic Weapons. The Beneficiary Clay Golem's weapon attacks are magical.

Multiattack. The Beneficiary Clay Golem makes two melee attacks. It can only use one Heavy Slam attack at a time.

Punch. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) bludgeoning damage. If the Beneficiary Clay Golem is currently holding another creature within its hand, then the grappled creature takes 7 (2d6) bludgeoning damage.

Kick. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage. If the target is a Medium or smaller creature, the target must succeed on a DC 16 Strength saving throw or be knocked prone. If the creature is Large or bigger then it has an advantage on the saving throw.

Heavy Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 16 (2d10 + 5) bludgeoning damage. If the target is a creature, it must succeed on a DC 15 Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. The target dies if this attack reduces its hit point maximum to 0. The reduction lasts until removed by the greater restoration spell or other magic.

Haste (Recharge 5–6). Until the end of its next turn, the Beneficiary Clay Golem magically gains a +2 bonus to its AC, has advantage on Dexterity saving throws, and can use its Heavy Slam attack as a bonus action.

Grapple. As a bonus action on a successful punch attack, the Beneficiary Clay Golem can grapple the target. If the target is a Medium or smaller creature, the target must succeed on a DC 16 Strength saving throw or it is Grappled (escape DC 16). 

Arcane Refection.  If the Beneficiary Clay Golem is hit by a ranged spell attack, as a reaction the golem may reflect any damage back to the caster. The Beneficiary Clay Golem takes no damage and the caster is considered the target of the spell. The Beneficiary Clay Golem raises its arms and places it together to form an oval mirror that shimmers once activated and fades once the Beneficiary Clay Golem moves its arms apart.

After each magical attack that is reflected, roll a d20. On a 1 the mirror breaks, no longer being useful and looses all magical ability to reflect spells. If this ability is used repeatedly before a long rest then subtract 1 for each spell reflected.