The acid blob, b, is an amoeboid monster in NetHack. It is the first acidic monster most players will encounter, and also likely the first amorphous monster as well. Acid blobs do no damage on their own, but have an acid-splashing passive attack that can corrode weapons and armor.
Acid blob corpses are unique in that they are always fit for sacrifice, and do not become tainted from aging similar to lichen and lizard corpses, though they can still rot away. Eating an acid blob corpse will do 1d15 damage unless you are acid resistant; a tin of acid blob will not do any damage. Acid blob corpses are considered vegan-friendly.
Acid blobs will act the same as any other hostile monster, but are ultimately harmless; however, attacking them poses a threat to an inexperienced and/or low-level player, and their amorphous forms allow them to ooze under doors and block a player's path.
For some early characters, it is best to dispatch them at a distance with disposable projectiles like rocks, or non-iron projectiles such as elven daggers. Wands and spells can work, but are better saved for more direct threats. If you have enough HP to survive a few splashes of acid, then use a disposable/non-iron weapon, attack bare-handed, or simply kick them; the acid splash may still affect any corrodible armor.
Past this point, acid blobs are little more than a nuisance that can occasionally erode weapons and armor if a player is careless in dispatching them, and proper erode-proofing mitigates even that annoyance. However, acid blob corpses have value both as long-lasting sacrifice fodder and a means of curing stoning - acid blob tins can cure it without dealing acid damage, but may take too long to safely open unless blessed.
Later in the game, players may employ confused readings of scrolls of create monster to fill up a dungeon level with acid blobs and prevent other monsters from approaching; this is also occasionally employed to stop the Riders on the Astral Plane from reviving.
- See the encyclopedia entry for amoeboid.