In Greek mythology, which creature is known as the Hound of Hades?
And the answer: Cerberus.
Known as the Hound of Hades, Cerberus is a dog with multiple heads who guards the gates of the Underworld to prevent the dead from leaving. Cerberus is usually described as having three heads, a serpent or dragon for a tail, and snakes protruding from parts of his body.
As most groups of three in Greek mythology, the three heads of Cerberus are said to symbolize three immutable aspects of life. While some believe they represent the past, present and future, others believe the symbolism is intended to represent the progression from birth to life to old age.
Cerberus is said to possess the ability to turn intruders to stone with just his gaze, much like the fated Medusa and her Gorgon sisters. Yet, if that wasn't enough, his razor-sharp teeth and poisonous bite are well-equipped to keep out even the most adventurous of heroes (though, Hercules might be the exception, since he was able to "squeeze" the creature into submission, without harming him).
Cerberus' fearsome power is drawn from his monstrous parentage. Typhon, his father, was considered the mightiest and deadliest monster in Greek mythology. As the last son of Gaea and Tartarus, Typhon was created as a last attempt to repel the Olympian gods from defeating the Titans during the Titanomachy (that's the war between the Titans, the older generation of gods, and the Olympians, the younger generations). And Cerberus' mother, Echidna, was a half-woman, half-snake creature in Greek mythology, also known as the "mother of all monsters," as she gave birth to most of the Greek mythical creatures.
Learn more about Cerberus here.