Cheese Golem

Berserk. Whenever the golem starts its turn with 25 hit points or fewer, roll a d6. On a 6, the golem goes berserk. On each of its turns while berserk, the golem attacks the nearest creature it can see. If no creature is near enough to move to and attack, the golem attacks an object, with preference for an object smaller than itself. Once the golem goes berserk, it remains so until it is destroyed or regains all its hit points.

The golem's creator, if within 60 feet of the berserk golem, can try to calm it by speaking firmly and persuasively. The golem must be able to hear its creator, who must take an action to make a DC 13 Charisma (Persuasion) check. If the check succeeds, the golem ceases being berserk. If it takes damage while still at 25 hit points or fewer, the golem might go berserk again.

Meltable. If the golem takes fire damage, it has disadvantage on attack rolls and ability checks, and its speed is reduced by 10 feet, until the end of its next turn. It can't use its Engulf attack unless it is under these effects, and it doesn't suffer disadvantage on its attack rolls for it.

Hardened Exterior. If the golem takes cold damage during a single turn, its exterior hardens, granting it a +1 to its AC until it takes fire damage equal to or greater than the amount of cold damage that was dealt to it. This effect is cumulative but can't increase the golem's AC above 16.

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

Poison Absorption. Whenever the golem is subjected to poison damage, it takes no damage and instead regains a number of hit points equal to the poison damage dealt.

Magic Resistance. The golem has advantage on saving throws against spells and other magical effects.

Magic Weapons. The golem's weapon attacks are magical.

Multiattack. The golem makes two slam attacks.

Slam. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage.

Engulf. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 4 (1d8) fire damage. A Medium or smaller creature is also grappled (escape DC 15). Until this grapple ends, the target is restrained, the golem has advantage on attacks against it, and the golem can't grapple another creature. The golem can't willingly end such a grapple.