Black Pudding 1977 AD&D MM

The black pudding is a monster composed of groups of single cells. It is a scavenger/hunger found only in underground areas normally. The body structure of a black pudding is such that it can pass (flow) through narrow openings (such as a 1" crack under a door). The monster travels equally well on walls or ceilings as floors. Its tiny mouths and saliva do 3-24 hit points of damage per melee round to exposed flesh. If the monster needs to dissolve wood in order to obtain food, it can eat away about a two-inch thickness of wood qual in area to its diameter in 1 melee round. Black puddings also eat away metal with their corrosive saliva: Chainmail in 1 melee round, plate mail in 2, and an additional melee round for magical armor at a rate of 1 melee round for each plus of armor. Thus, +1 magic (plate) armor would have to be in contact with a black pudding for 3 melee rounds before it dissolved. If chopped or struck, the monster is broken into two or more parts, each able to attack. The same is true if it is attacked by lightning. Cold does not affect it. Fire causes normal damage to this monster, and they avoid flames. Black puddings sometimes have color variation, grey, brown, and white being not uncommon.

Black puddings with 10-20 hit points are about 5' diameter, those of 21-40 hit points 6'. and 61-80 are 8'. Note that even those of the smallest size (or those as small as 1' diameter) are able to deliver normal damage. This is due to the fact that larger puddings simply do not use all of their mouth openings as they are not exposed.