Black Conglomerate Golem

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

Berserk Oozeform. Whenever the golem starts its turn with 60 hit points or fewer, roll a d4. On a 4, the golem goes berserk, and melts into an Oozeform, increasing it's speed. 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 continues to do so until it is destroyed or regains all its hit points. It turns back from an ooze 1d4 rounds after it has left the Beserk state.

Oozeform. While in Oozeform, the golem gains the following traits:

• Amorphous. The Oozeform can move through a space as narrow as 1 inch wide without squeezing.
• Spiderclimb. The Oozeform can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

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

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

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

Corrosive Form. A creature that touches the golem or hits it with a melee attack while within 5 feet of it takes 4 (1d8) acid damage. Any nonmagical weapon made of metal or wood that hits the golem corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed.

Nonmagical ammunition made of metal or wood that hits the golem is destroyed after dealing damage.

The golem can eat through 2-inch-thick, nonmagical wood or metal in 1 round.

Split. When a golem that is Medium or larger is subjected to lightning or slashing damage, it splits into two new golems if it has at least 10 hit points. Each new golem has hit points equal to half the original golem's, rounded down. New golems are one size smaller than the original golem. If it is split in Oozeform, the resulting creatures are plain black oozes, as described on p. 241 of the Monster Manual. As an action, these Oozes can reform into a normal Golem.

Multiattack. The golem makes two slam attacks, or two Pseudopod attacks if in Oozeform.

Slam. (Golem Only) Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 16 (2d10 + 5) bludgeoning damage plus 18 (4d8) acid 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 (Golem Only) (Recharge 5–6). Until the end of its next turn, the golem magically gains a +2 bonus to its AC, has advantage on Dexterity saving throws, and can use its slam attack as a bonus action.

Pseudopod. (Oozeform Only) Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) bludgeoning damage plus 18 (4d8) acid damage. In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.

Consume. If a creature is reduced to 0 hit points by one of the golems attacks, the creature dies and is consumed by the golem, restoring however much hp the consumed creature had the turn before.