Gray Ooze

Medium ooze, unaligned

Armor Class 8
Hit Points 22 (3d8 + 9)
Speed 10 ft., climb 10 ft.

Skills Stealth +2
Damage Resistances acid, cold, fire
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone
Senses blindsight 60 ft. (blind beyond this radius), passive Perception 8
Languages --
Challenge 1/2 (100 XP)

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.

Actions

Pseudopod. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage plus 7 (2d6) 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.