Corrosive Body. Any creature or object that comes in contact with the Sludge Like takes the risk of being corroded or even dissolved. A creature that touches the Sludge Like or hits it with a melee attack while within 5 feet of it takes 8 (2d8) acid damage. Any nonmagical weapon that hits the Sludge Like corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to attack and damage rolls. If its penalty drops to −5, the weapon is destroyed. Any nonmagical armor or shield that touches the Sludge Like takes a permanent and cumulative -1 penalty to its AC. If the granted AC falls to 10 or below, it is destroyed.

Nonmagical ammunition that hits the Sludge Like is destroyed after dealing damage.

The Sludge Like can eat through 12-inch-thick, nonmagical wood or metal in 1 round.

Corrosive Insides: The corrosive enzymes of the Sludge Like are stronger on the inside.  Any object that is swallowed by the Sludge Like has a chance of corroding or dissolving beyond repair. At the start of each of the Sludge Like's turns, roll a d6 for each object that is swallowed by, or worn or wielded by a creature that is swallowed by the Sludge Like. For nonmagical objects: On a 6, any nonmagical object is destroyed. On a 4 or 5, any nonmagical weapon takes a permanent and cumulative −1 penalty to attack and damage rolls, dissolving if the penalty drops to −5. Also on a 4 or 5, any nonmagical armor or shield takes a permanent and cumulative -1 penalty to its AC. If the granted AC falls to 10 or below, it is destroyed. For magical objects: On a 6, any magical weapon suffers a permanent and cumulative −1 penalty to attack and damage rolls. If its penalty drops to −5, the weapon is destroyed. Also on a 6, any magical armor or shield takes a permanent and cumulative -1 penalty to its AC. If the granted AC falls to 10 or below, it is destroyed. For other magical objects with a rarity below "Rare", roll a d20. On a 1, the object loses any magical properties. 

 The Sludge Like's Corrosive Insides ceases while it is incapacitated or otherwise unable to take actions on its turn.

Spider Climb. The Sludge Like can adhere to and climb difficult surfaces, including upside down on ceilings, without needing to make an ability check. 

Sludge Coating.  The surface in a 10-feet radius of the Sludge Like is constantly coated in a viscous brown sludge. This is treated as difficult terrain. Any creature who begins their turn in this sludge or enters it on their turn must make a Dexterity saving throw (DC 12) or suffer 3 (1d6) acid damage. If the Sludge Like moves, the area of sludge moves with it. 

Water Vulnerability.  If exposed to 10 or more gallons of water, or the equivalent in rainfall, the Sludge Coating property of the Sludge Like is nullified until the end of its next turn. Additionally, until the end of its next turn, the Sludge Like's AC becomes 12, and the Sludge Like gains a vulnerability to cold, fire, and lightning damage. Any sludge created by Sludge Coating or Sludge Shot can be removed on a one gallon of water to one square foot of sludge ratio.

Pseudopod. 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.

Sludge Shot. Ranged Attack: +5 to hit, reach 30 ft., one target. Hit: 9 (2d6+ 3) acid damage. On a hit, the area in a 5-foot radius of the target is coated in a viscous brown sludge, which suffers the same effects as terrain describe in Sludge Coating.

Swallow. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (2d6 + 3) bludgeoning damage plus 12 (3d8) acid damage, and the target is grappled (escape DC 15). Until this grapple ends, the target is restrained, it has total cover against targets outside the Sludge Like, and the Sludge Like can't swallow another target. While grappled, the target takes 8(2d8) acid damage at the start of each of the Sludge Like's turns. While the target is swallowed, the Sludge Like can't use its swallow action. If the target escapes this grapple, it must succeed on a DC 15 Dexterity saving throw, or drop everything it was holding into the Sludge Like, subjecting the objects to the creature's Corrosive Insides trait.