Bašmu or Bashmu (lit. “Venomous Snake”) was an ancient Mesopotamian mythological creature, a horned snake with two forelegs and wings. It was also the Akkadian name of the Babylonian constellation equivalent to the Greek Hydra. The Sumerian terms ušum (portrayed with feet, see Ninurta’s Dragon) and muš-šà-tùr (“birth goddess snake”, portrayed without feet) may represent differing iconographic types or different demons.

It was one of the eleven monsters created by Tiamat in the Enuma Elish creation myth. It had “six mouths, seven tongues and seven …-s on its belly”.

wikipedia

Right-o. Hydra goddess. Possible ancestral source of snake-like monsters, the way Kusarikku is the ancestor of beast-like humanoids. Hrm. Where do lizardfolk come from?

Hydra

• Hit Dice: 5-12 (equal to the number of heads)
• Armor Class: [14]
• Attacks: 5-12 bites (1d6)
• Saving Throw: 12, 11, 9, 8, 6, 5, 4, or 3
• Special: None
• Move: 9
• Alignment: Neutrality
• Challenge Level/XP: 5 HD (7/600), 6 HD (8/800), 7 HD (9/1,100), 8 HD (10/1,400), 9 HD, (11/1,700), 10 HD (12/2,000), 11 HD (13/2,300), 12 HD (14/2,600)

Hydras are reptile-like monsters with 1d8+4 heads. A hydra is gray-brown to dark brown, with a light yellow or tan underbelly. The eyes are amber and the teeth are yellowwhite. It is about 20 feet long and weighs about 4,000 pounds. Hydras have a number of hit die equal to their number of heads. They have maximum hit points for their hit die. Each head attempts to bite an opponent in a round, so the number of attacks a hydra has each round is equal to the number of heads it has. When a hydra has suffered 8 hit
points of damage, 1 head becomes useless. For each additional 8 hp damage, another head becomes useless, until all heads have been destroyed and the hydra dies.

Labyrinth Lord

It is a matter of good strategy for adventurers to focus either on killing heads (when all the heads are dead the body dies) or killing the creature by attacking the body (in which case the heads die, too). Hydrae that breathe fire or regenerate their heads are also known to exist.

Swords & Wizardry