Medusa was one of the three Gorgons of Greek mythology. They were ugly in some stories and beautiful in others, but usually depicted as having serpents in place of hair, and the power of petrify whoever looked at their heads. Medusa was the only mortal one out of the three, and was slain by Perseus.
メデューサの矢 / メデューサのや [medusa no ya] or 'Medusa Arrow' in Japanese.
Final Fantasy III

Stats: ATK 23, ACC 75, weight 0, inflicts Gradual Petrification
Use: ONK, RNG
Buy: 300 gil (sell: ? gil)
Shop: Ancient Ruins, Invincible
Drop: Demon, Parademon
Treasure: Castle Argus, Castle Saronia
Type: Arrow
Final Fantasy IV
Stats: ATK 20, ACC 80
Equip: Rosa
Buy: - (sell: 25 gil)
Drop: Black Lizard, Gorgon, Medusa, Stone Golem
Treasure: Sylph Cave
Other: chance of inflicting break
Category: Item