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

Corrode Metal. Any nonmagical weapon made of metal that hits the ooze 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 that hits the ooze is destroyed after dealing damage.

The ooze can eat through 2-inch-thick, nonmagical metal in 1 round.

False Appearance. While the ooze remains motionless, it is indistinguishable from an oily pool or wet rock.

Acidic Explosion. When this monster is reduced to 0 hp, anything within a 10x10ft square is coated in acid. This acid deals 2d6 acid damage on impact and 1d4 damage every minute until removed

Corosive Blob. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (2d8 + 1) Acid damage plus 1 (2d8) acid damage, and if the target is wearing nonmagical metal armor, its armor is partly corroded 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.