Brain pudding

Amorphous. The pudding can move through a space as narrow as one inch without squeezing.

Corrosive Form. A creature that touches the pudding or hits it with a melee attack while within 5 feet of it takes (1d6) acid damage. Any nonmagical weapon made of metal or wood that hits the pudding 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 pudding is destroyed after dealing damage.

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

Brainfreeze. if the Brain pudding takes cold damage, it has disadantage on attack rolls and ability checks until the end of it's next turn

Telepathy. the pudding can telepathically communicate with any creature within 100 ft  if it is aware of the creatures position.

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

Pseudopod. Melee Weapon Attack:  to hit, reach 5 ft., one target. Hit:  (1d6 + 2) bludgeoning damage plus (2d6+4)  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.

Psychic Crush (Recharge 5–6). The Ooze targets one creature it can sense within 60 feet of it. The target must make a DC 10 intelligence saving throw, taking (3d6) psychic damage on a failed save, or half as much on a successful one

Spellcasting (Psionics). The Brain Pudding casts one of the following spells, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 13):

At Will: Acid splash

3/day each: shield (reaction), charm person

2/day each: command

Shield. As a reaction the pudding can cast shield before it is hit by an attack potentially causing the attack to miss and blocking all damage if it is hit with magic missile