In Greek mythology, the term "hydra" refers to a multi-headed serpent-like monster. Each time a head was cut off, two more would grow in its place, symbolizing regeneration and monstrous challenges. The Hydra of Lerna was ultimately slayed by Heracles as one of his twelve labors. This mythical creature represents the obstacles and fears that one must face, often portraying the theme of overcoming seemingly impossible odds through courage and cunning.