b'Gearmass \n'b'  Large   ooze ,  unaligned  \n'b'  Armor Class  15 (natural armor)  Hit Points  115 (11d10 + 55)  Speed  20 ft., swim 20 ft.\n'b' STATS STR: 16 (+3) DEX:  5 (\xe2\x80\x933)  CON:  20 (+5)  INT:  1 (\xe2\x80\x935)  WIS:  6 (\xe2\x80\x932)  CHA:  1 (\xe2\x80\x935)  \n'b'\n'b'\n'b'\n'b'\n'b'\n'b'\n'b'  Damage Vulnerabilities  cold  Damage Resistances  bludgeoning, piercing, and slashing from nonmagical attacks  Damage Immunities  acid, fire Condition Immunities  blinded ,  charmed ,  deafened ,  exhaustion ,  frightened ,  prone   Senses  blindsight 60 ft. (blind beyond this radius), passive  Perception  8  Languages  \xe2\x80\x94  Challenge  5 (1,800 XP)  Proficiency Bonus  +3 \n'b' SPECIAL TRAITS \n'b'\n'b'  Amorphous . The gearmass can move through a space as narrow as 1 foot wide without squeezing. \n'b'  Clanging Mass . The gearmass is filled with metal objects that clang, scrape, and clink together as it moves. When it moves, it has disadvantage on  Dexterity  ( Stealth ) checks to stay silent until the start of its next turn. \n'b'  Ooze Nature . The gearmass doesn\xe2\x80\x99t require sleep. \n'b'  Rust Metal . Any nonmagical weapon made of metal that hits the gearmass corrodes. After dealing damage, the weapon takes a permanent and cumulative \xe2\x80\x931 penalty to  damage rolls . If its penalty drops to \xe2\x80\x935, the weapon is destroyed. Nonmagical ammunition made of metal that hits the gearmass is destroyed after dealing damage. \n'b'\n'b' ACTIONS \n'b'\n'b'  Multiattack . The gearmass makes two Gear Slam or Cog Toss attacks. If it hits one creature with both Gear Slam attacks, the target is  grappled  (escape DC 14), and the gearmass uses Engulf on the target. \n'b'  Gear Slam .  Melee Weapon Attack : +6 to hit, reach 10 ft., one creature.  Hit : 12 (2d8 + 3) bludgeoning damage. \n'b'  Cog Toss .  Ranged Weapon Attack : +6 to hit, reach 20/60 ft., one creature.  Hit : 12 (2d8 + 3) bludgeoning damage, and the target must succeed on a DC 14  Strength  saving throw or be knocked  prone . \n'b'  Engulf . The gearmass engulfs a Medium or smaller creature  grappled  by it. The engulfed target is  blinded ,  restrained , and unable to breathe, and it must succeed on a DC 14  Constitution  saving throw at the start of each of the gearmass\xe2\x80\x99s turns or take 14 (4d6) acid damage. Any nonmagical ferrous metal armor, weapons, or other items the target is wearing corrode at the start of each of the gearmass\xe2\x80\x99s turns. If an object is either metal armor or a metal  shield  being worn or carried, it takes a permanent and cumulative \xe2\x80\x931 penalty to the AC it offers. Armor reduced to an AC of 10 or a shield that drops to a +0 bonus is destroyed. If an object is a metal weapon, it rusts as described in the Rust Metal trait. If the gearmass moves, the engulfed target moves with it. The gearmass can have only one creature engulfed at a time. \n'b'\n'b' ABOUT \n'b' A cacophony of banging metal and burbling pops echoes down the corridor before a pile of metal junk encased in a greasy bubble turns the corner and seeps down the hall. \n'b' A gearmass appears as a shambling ooze full of metal junk. It collects and carries discarded bits left by tinkers, machinists, and dead constructs, slowly feeding off the rust its acid promotes in the metal. Gearmasses are not stealthy, nor quiet in the least, a saving grace for dungeon delvers encountering them. However, all too often, the metal clanging racket is so confusing that by the time curious adventurers recognize their quarry, it is too late. \n'b'  Lazy Mages are the Worst . The first gearmass was crafted by a  wizard  who wanted the cleaning power of a  gelatinous cube  combined with the scouring potential of a  rust monster . \n'b' Unfortunately, the oddball creation escaped during an impromptu encounter with some zealous heroes. Unchecked and uncaged, the first gearmass quickly proliferated. A few daring wizards have since captured and trained the offspring, but the risks of keeping such creatures in laboratories and workshops quickly become apparent as the creatures devour all nearby metal.'