Name: Medusa
Difficulty: 25
Base level: 20
Base experience: 633
Speed: 12
Base AC: 2
Base MR: 50
Alignment: -15
Frequency: unique, no random generation
Genocidable: No
    Claw: 1d8
    Gaze turns to stone
    Bite: Strength draining poison
    Projectile as weapon, or if in range, uses melee weapon for 2d4
Weight: 1450
Nutritional value: 400
Size: large
Resistances: poison, petrification
Resistances conveyed by eating: poison

Medusa can fly/float, and traverse water. She in amphibious. She is humanoid. She is poisonous if eaten. Medusa is an omnivore.

Medusa, one of the three Gorgons or Graeae, is the only one of her sisters to have assumed mortal form and inhabited the dungeon world. When Perseus was grown up Polydectes sent him to attempt the conquest of Medusa, a terrible monster who had laid waste the country. She was once a beautiful maiden whose hair was her chief glory, but as she dared to vie in beauty with Minerva, the goddess deprived her of her charms and changed her beautiful ringlets into hissing serpents. She became a cruel monster of so frightful an aspect that no living thing could behold her without being turned into stone. All around the cavern where she dwelt might be seen the stony figures of men and animals which had chanced to catch a glimpse of her and had been petrified with the sight. Perseus, favoured by Minerva and Mercury, the former of whom lent him her shield and the latter his winged shoes, approached Medusa while she slept and taking care not to look directly at her, but guided by her image reflected in the bright shield which he bore, he cut off her head and gave it to Minerva, who fixed it in the middle of her Aegis.
Bulfinch's Mythology, by Thomas Bulfinch