Devils (usually) live in the cavernous bowels of Hell, but demons are another thing entirely: mutated spells with psychoplasmic bodies. The Squeaking Immaculus, or sponge demon, is produced from Randolph’s abrasive cleanser, which doesn’t find much use among dungeon delvers for some reason.
The biggest trouble with Squeaking Immaculi is that they can hold all kinds of liquids, including potions, for later use. The second biggest trouble is that they’re clever enough to use this to their full advantage, turning invisible at a moment’s notice and crawling up the walls with a potion of spider climb to make an unseen attack from above, or spraying the party with oil and then using a potion of fire breath on its next turn.
When it comes to sponge demons, oozes count as “liquid” and may be soaked up (and spewed out) like anything else, which makes them indispensable to alchemists (whose experiments can produce oozes when they go wrong).
Rules for the Squeaking Immaculus, and for Randolph’s abrasive cleanser, below the cut.