Amorphous. The pudding can move through a space as narrow as 1 inch wide without squeezing.
Corrosive Form. A creature that touches the pudding or hits it with a melee attack while within 5 feet of it takes 4 (1 d8) acid damage. Any nonmagical weapon made of metal or wood that hits the pudding corrodes. After dealing damage, the weapon takes a permanent cumulative -1 penalty to damage rolls. If its penalty drops to -5, the weapon is destroyed. Non magical ammunition made of metal br wood that hits the pudding is destroyed after dealing damage.
The pudding can eat through 2-inch-thick, non magical wood or metal in 1 round.
Spider Climb. The pudding can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
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, non magical 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.
Split. When a pudding that is Medium or larger is subjected to lightning or slashing damage, it splits into two new puddings if it has at least 10 hit points. Each new pudding has hit points equal to half the original pudding's, rounded down. New puddings are one size smaller than the original pudding.
A  black pudding resembles a heaving mound of sticky black sludge. In dim passageways, the pudding appears to be little more than a blot of shadow. Flesh, wood, metal, and bone dissolve when the pudding ebbs over them. Stone remains behind, wiped clean.
Ooze Cube. The cube takes up its entire space. Other creatures can enter the space, but a creature that does so is subjected to the cube's Engulf and has disadvantage on the saving throw. Creatures inside the cube can be seen but have total cover.
A creature within 5 feet of the cube can take an action to pull a creature or object out of the cube. Doing so requires a successful DC 12 Strength check, and the creature making the attempt takes 10 (3d6) acid damage.
The cube can hold only one Large creature or up to four Medium or smaller creatures inside it at a time.
Transparent. Even when .the cube is in plain sight, it takes a successful DC 15 Wisdom (Perception) check to spot a cube that has neither moved nor attacked. A creature tbat tries to enter the cube's space while unaware of the cube is surprised by the cube.
Pseudopod. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 10 (3d6) acid damage.
Engulf. The cube moves up to its speed. While doing so, it can enter Large or smaller creatures' spaces. Whenever the cube enters a creature's space, the creature must make a DC 12 Dexterity saving throw.
On a successful save, the creature can choose to be pushed 5 feet back or to the side of the cube. A creature that chooses not to be pushed suffers the consequences of a failed saving throw.
On a failed save, the cube enters the creature's space, and the creature takes 10 (3d6) acid damage and is engulfed. The engulfed creature can't breathe, is restrained, and takes 21 (6d6) acid damage at the start of each of the cube's turns. When the cube moves, the engulfed creature moves with it.
An engulfed creature can try to escape by taking an action to make a DC 12 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the cube.
Gelatinous cubes scour dungeon passages in silent, predictable patterns, leaving perfectly clean paths in their wake. They consume living tissue while leaving bones and other materials undissolved.
A gelatinous cube is all but transparent, making it hard to spot until it attacks. A cube that is well fed can be easier to spot, since its victims' bones, coins, and other 9bjects can be seen suspended inside the creature.