In Greek mythology, the Lernaean Hydra ( Greek: Λερναία Ὓδρα) was an ancient serpent-like water monster with reptilian traits. It possessed many heads - the poets mention more heads than the vase-painters could paint - and for each head cut off it grew two more.
The twelve labours of Hercules or dodekathlon ( Greek: δωδέκαθλον, dodekathlon) are a series of episodes concerning a penance carried out by Heracles, the greatest of the Greek heroes, whose name was later Romanised as Hercules.