Hydra of Lerna

This is the Hydra of Lerna, its a greek mythological creature, it guards the gates of the underworld, it is a serpentine mythical creature, its lair is the lake of lerna. Its breathe is poisonous and even the smell of its blood can kill you, this hydra possesed many heads, for every head cut off 2 more would grow in its place. The only way to kill it is Hercules and his nephew lolaus.