The Mythological Tarasconus For Your Old School Adventures & Campaigns

 " The Tarasque is a fearsome legendary dragon-like mythological hybrid from Provence, in southern France, tamed in stories about Saint Martha, such as the one told in Jacobus de Voragine's Golden Legend (13th century)."

The tarasque was described as having a lion-like head, a body protected by turtle-like carapace(s), six feet with bear-like claws, and a scaly tail like a serpent's tail in a text (pseudo-Marcelle or pseudo-Marcella) which is similar to and roughly coeval with the Golden Legend, and issued poison breath according to one hagiography (pseudo-Raban Maur) of perhaps somewhat later date."

No. Enc.: 0 (1d3) Alignment: Chaotic  Movement: Swim: 90’ (30’) Armor Class: 5 Hit Dice:  15  Attacks:4 Claw, Claw, Tail Sting, Breath Weapon  Damage: 2d6 Claw Strike, 3d6 Tail Sting, Breath Weapon  4d6 4 Times A Day, Dung Fling 2d6 Acidic Damage  3 times A Day Save: L4 Morale: 8 Horde Class: H 

The Tarasque (Latin: Tarasconus) was said to have come from Galatia, a cross-breed between the biblical Leviathan and the legendary Onachus (or onacho, or bonacho^[c][d]) of Galatia, this onachus being a creature that retaliated against pursuers by flinging its dung (Latin: stercus) like an arrow, and causing burns. 

A huge dragon, half animal, half fish... fatter than a bull, longer than a horse, it had the face and head of a lion, teeth sharp as swords, the mane of a horse, a back that was hatchet-sharp with bristly scales keen as augers, six feet with bear-like claws, the tail of a serpent, and a double shield/carapace, like a tortoise's, on each side.

A terrible dragon of unbelievable length and great bulk. It breathed out poisonous fumes, shot sulfurous flames from its eyes, and emitted fierce hissings with its mouth and horrible noises with its curved teeth. With its talons and teeth it tore to pieces anyone who crossed its path; with its poisonous breath it killed anyone who came too near.

The Tarasconus was a product of the Pre Biblical Flood & is a  creature of absolute malice & Chaos. The dragon like horror is capable of devouring the flesh of anyone that crosses its path. And will attack with its deadly claws at the first chance it gets devouring horse and rider easily. The Tarasconus has the ability to breath out poisonous fumes four times per day devestating plant life, flesh, and anything else that it comes into contact with it. The way to heal from this breath weapon is to use a  only remove curse spell  and magical healing has any chance of healing anyone caught in its wake. The Tarasconus will also fling its offal at anyone trying to pursue it on horse back or in a body of water. The offal is highly acidic causing horrid burns to any metal or  exposed flesh. The Tarasconus is known to destory entire cities, towns, and other urban areas out of a sheerly evil nature. The Tarasconus has reproduced due to the mating with certain undisclosed infernal dragons. There is gossip in certain occult circles that Tiamat or her mates were involved in these matters. 

The Tarasconus can be cast out by a cleric of 7th level or better but only a saint can cow the monster due its semi infernal nature. These monsters are often released by the Chaos gods to sew discord on the prime material plane