New OSR Monster - The Giant Venomous Sewer Snail For Your Old School Campaigns

Spawning deep beneath the sewer systems of the urban centers and ruins of Accursed Atlantis is the giant venomous  sewer snail. Created by the elder things far back in the mists of time, these giant creatures act as giant wrecking crews slowly clearing out areas and ancient passages of any vermin or pests that they find this includes humans and near humans. They are attracted to rot, ruin, and the smell of humanoids.
                                                 

                                                                          Frequency: Uncommon

                                                                            No Appearing: 1d4 

                                                                                Armor Class:7 

                                                                                    Move: 6"

                                                                                Hit Dice: 13 

                                                                            Treasure Type: Q

                                                                                 Dexterity: 8 

                                                                          Number of Attacks: 1 

                                                                        Damage /Attacks: 3d6 

                                                                 Special Attacks: Poison Barb 

                                                                 Special Defenses: See Below 

                                                                   Magic Resistance: Standard
                                                                          Intelligence: Non
                                                                        Alignment: Neutral 

                                                                             Size: Large 

                                                                        Psionic Ability: Non 

                                                                      Attack/Defense:Non

                                 

The giant venomous sewer snail is an opportunist of the highest order which preys on humanoids of all types that enter its ruins or dungeon. The giant monster blends into its environment by appearing to be a part of background of the place. This technique has a 15% chance of working as the monster's skin and shell mystic change colour to suit its surroundings. The sewer snail spits out a foot long barbed dart outwards of 20 feet at its prey. Those hit by this barbed dart like object must save vs death or immediately have its cocktail of flesh dissolving poisons and acidic horror rip apart its victim from the inside out. The giant venomous sewer slug is an artificially created monster that regenerates any damage sustained as per a troll's regeneration ability . Only fire damage can not be regenerated. Those who survive the acidic damage of a bite rarely escape the ravenous nature of the poisonous creatures. They hunt in slow moving packs of four giant animals, ponderously moving from room to room hunting for prey. Giant venomous sewer snails are an all too common invasive species of monster to encounter in the dungeons and ruins of Accursed Atlantis. They are considered a menace of the highest order and some urban city states have standing rewards of 300 gold pieces for the extermination of these horrors. 
The sewer snails have an automatic instinct to collect any and all relics left behind by their prey and web these relics and finds into slime covered trophies to attract more prey. Those who survive tangles with  giant venomous sewer snail packs have a 30% chance of being infected with egg casings under their skin from these monsters. The babies will develop and eat their way out of the prey within 1d4 weeks their by killing their prey. Only expensive magical healing or super science medical treatment has any chance of purging these creatures from the flesh of their victims.