Flesh Guardian

Medium Construct

STR	DEX	CON	INT	WIS	CHA
18 (+4)	8 (-1)	18 (+4)	6 (-2)	10 (+0)	5 (-3)

Skills:
Damage Immunities: lightning, poison; damage from nonmagical, non-adamantine weapons
Condition Immunities: charmed, fatigue, frightened, paralyzed, petrified, poisoned
Senses: darkvision 60 ft., passive Perception 10
Languages: understands the languages of its creator but can't speak

Berserk: When the guardian starts its turn while bloodied, roll a d6. On a 6, the guardian goes berserk. While berserk, the guardian attacks the nearest creature it can see. If it can't reach a creature, it attacks an object. The guardian stays berserk until it is destroyed or restored to full hit points.
If a berserk guardian can see and hear its creator, the creator can use an action to try to calm it by making a DC 15 Persuasion check: On a success, the guardian is no longer berserk.
Fire Fear: When the guardian takes fire damage, it is rattled until the end of its next turn.
Immutable Form: The guardian is immune to any effect that would alter its form.
Lightning Absorption: When the guardian is subjected to lightning damage, it instead regains hit points equal to the lightning damage dealt.
Magic Resistance: The guardian has advantage on saving throws against spells and magical effects.
Constructed Nature: Guardians dont require air, sustenance, or sleep.

Multiattack: The guardian attacks twice with its slam.
Slam: Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.
Hurl Object: Ranged Weapon Attack: +7 to hit, range 20/60 ft., one target. Hit: 18 (4d6 + 4) bludgeoning damage.
Lightning Bolt (1/Day, While Bloodied): An 80-foot-long 5-foot-wide lightning bolt springs from the guardians chest. Each creature in the area makes a DC 15 Dexterity saving throw taking 28 (8d6) lightning damage on a failed save or half damage on a success.