Amorphous. The slime can move through a space as narrow as 1 inch wide without squeezing.

Corrosive Body. Any creature that touches the slime or hits it with a melee attack while within 5 feet takes 9 (2d8) acid damage. Nonmagical weapons that strike the slime corrode: 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. (Magical weapons are immune.)

Divide. When reduced to 30 hit points or fewer, the slime splits into two smaller slimes (Medium, each with half its current HP).

Split Reaction. When the slime takes slashing or lightning damage, it splits into two new slimes, each with half the original’s hit points.

Acidic Hunger. The slime’s body constantly secretes an otherworldly digestive acid. Any creature that starts its turn grappled by the slime takes 2d8 acid damage, and any nonmagical weapon or piece of armor that strikes or touches the slime corrodes. After dealing damage to the slime with a nonmagical metal weapon, the weapon takes a −1 penalty to attack and damage rolls. If its penalty reaches −5, the weapon is dissolved. Nonmagical armor or shields touching the slime have their AC reduced by 1 per round of contact. At AC 10, the item melts into bubbling residue. The slime heals 5 hit points per item or weapon it completely dissolves — representing its feeding frenzy.

Vile Intelligence. While seemingly mindless, this slime is a cunning mimic of its victims’ voices, habits, and even tactics. It can “remember” phrases and taunts spoken in its presence and uses them to lure the curious or separated. The slime has Advantage on Deception checks made to imitate sounds or voices it has heard. When in dim light or darkness, it can project illusory echoes (as the Minor Illusion cantrip, no concentration required) to mislead prey. Adventurers who fail a DC 14 Insight check may mistake its vocalizations for an ally in distress. Occasionally, its bubbling form coalesces into vague faces of past victims — hinting at absorbed memories.

Engorged Consumption. When the slime has absorbed enough matter — typically 50 pounds of material, or after fully dissolving a Medium creature or the equivalent in weapons and gear — it spawns a new Viscous Vicious Slime. The newborn slime oozes forth from its parent’s mass, initially at half HP but growing to full strength within 1 hour. If multiple slimes feed together, they can combine their digested matter into a Spawning Pool, producing a Greater Viscous Slime (Large size, double HP, and stronger acid damage). Each spawning leaves behind a patch of residual goo known as "Slime Spawn Husk", a faintly acidic, quivering residue that remains semi-alive for 1d4 hours — sometimes forming dangerous terrain.

Predatory Hunger. The slime is drawn toward living creatures and will always prioritize the closest source of life force.

Engulf. The slime moves up to its Speed without provoking Opportunity Attacks. The slime can move through the spaces of Large or smaller creatures if it has room inside itself to contain them (see the Ooze Cube trait). Dexterity Saving Throw: DC 14, each creature whose space the cube enters for the first time during this move. Failure: 14 (4d6) Acid damage, and the target is restrained, unable to breather. An engulfed target is suffocating, can’t cast spells with a Verbal component, has the Restrained condition, and takes 14 (4d6) Acid damage at the start of each of the slime’s turns. When the slime moves, the engulfed target moves with it. An engulfed target can try to escape by taking an action to make a DC 14 Strength (Athletics) check. On a successful check, the target escapes and enters the nearest unoccupied space. Success: Half damage, and the target moves to an unoccupied space within 5 feet of the cube. If there is no unoccupied space, the target fails the save instead.

Pseudopod. Melee Attack Roll: +5, reach 10 ft., one target. Hit: 13 (2d8 + 3) Bludgeoning damage plus 9 (2d8) Acid damage.