The heroes are the best-known part of Greek mythology, but what makes a hero? Having monsters to fight, that's what. Luckily for the heroes, the Greeks had the strangest, coolest, most terrifying monsters mythology had to offer — here is a baker's dozen of the best.
1) Cerberus
Most people know Cerberus as the three-headed dog who guards Hades — both keeping the living out and the dead in. While the idea of hell's guarddog by itself is pretty badass, most representations forget that Cerberus (like so many mythological Greek monsters) is a hodgepodge of other animal parts: He has the the claws of a lion, a mane made out of snakes, and a serpent's tail. Cerberus was the offspring of Typhon and the Chimera, which are both worthy entrants on this list. A few living people managed to sneak past Cerberus, with help from magic music or drugged food, but only Hercules straight-up defeated the beast.
2) Empousai
Empousai was an evil goddess, daughter of Hecate, who spent her evenings drinking the blood of young men while they slept. Over time, she was downgraded from a goddess to an entire species of monster who devoured travelers late at night. A transportation-based vampire is pretty freaky, but the Empousai also had one bronze leg and one goat leg for some reason, which makes them even freakier.
3) Gorgons
Perhaps the most well-known monsters of Greek mythology. These three sisters — Medusa, Stheno and Euryale — of course had hair made of living and extremely poisonous snakes, which seems a bit like overkill when just looking directly at their faces would also immediately petrify you. Often, the two non-Medusa sisters were also immortal; less occasionally, all three had giant fangs, like boar tusks. Of course, Medusa was defeated by the hero Perseus, but he needed help and equipment from Athena to do so. Otherwise there would have just been one more heroic-looking statue in the Gorgons' den.
4) Stymphalian Birds
Birds that attack people are generally considered scary on their own; Alfred Hitchcock proved that pretty effectively. But these birds, another monstrous species only Hercules could defeat, very specifically liked to eat people, which is terrifying; however, the real problem is that the birds' feathers were made of bronze, razor-sharp, and they could shoot them at people. These were not birds you shoo away, unless you also wanted your hand shredded into bloody flesh confetti. Again, Hercules had to deal with these guys as the sixth of his Twelve Labors, with help from a rattle made by the god Hephaestus, which scared them into taking off from the swamp they lived in, allowing Herc to shoot them down. Hey, they were deadly birds, but they were still birds.
5) Chimera
One of the most fascinating mix-n'-match monsters of Greek mythology, the Chimera had three heads, but only one of them was on its neck. The torso and main head was that of a lion. Then for some reason there was goat's head sticking out of its back. Then, for a tail, it had a snake — no, not a snake tail, just a snake, with its head as the tip. Also, it breathed fire, because why not. It was this strange ability that actually did it in; the hero Bellerophon threw spear with a tip of lead into its mouth; when the Chimera breathed its fire, the lead melted it inside, killing it. Just seeing the Chimera was an omen of some kind of horrible disaster, most often some sort of volcanic eruption.
6) Ichthyocentaurs
You know centaurs, obviously — the half-men, half-horse people who populate countless Greek myths. These guys were built like centaurs, except the back half of the horse part was actually the back half of a fish. They were like mermaids that had part of a horse grafted into the middle of them. They were actually pretty chill horse-fish-men, especially compared to their wild, hotheaded centaur brothers. They also pretty much had the powers of Aquaman, so that's cool.
7) Typhon
The big daddy of mythological Greek monsters — literally! It was literally the father of most of them. The last child of the primordial goddess Gaea, Typhon was as tall as the stars and his arm-span was from "east to west"; sources differ as to whether Typhon had a hundred dragon head on his neck or one giant human head (and dragon heads for fingers), but most agree that his body was covered in dragon wings and had hundreds of serpents for legs. Typhon could throw mountains at people he didn't like, and one person he didn't like was Zeus, the king of the gods. Typhon was so powerful he defeated Zeus and ripped out most of his muscles; Zeus only recovered because Hermes stole his muscles back later.
8) The Minotaur
Compared to some of the monsters on this list, the Minotaur is practically boring — it's a dude with a bull head. Not exactly hard to wrap your mind around. But there's a reason the Minotaur has always been one of Greek mythology's most famous monsters, and that's because it was an instant classic — a hideous monster, hidden away in a labyrinth, whose sole purpose was to kill the sacrificial children that got dumped in there as a yearly tribute. The fact that the Minotaur was born when his mother, Queen Pasiphae, wanted to have sex with a bull so badly she made a metal cow costume she could hide in that the bull would mount, well… that's just the salacious icing to monstrously classic cake.
9) The Furies
When the Titan Cronus castrated his dad Uranus and tossed his penis into the sea, like one does, the droplets of the blood that hit the ground became the Furies. Being born of severed genitalia blood, you could reasonably expect the Furies were not in particularly good moods; they spent their time finding people who had done wrong and tormenting them until they died horribly, primarily by whipping them repeatedly with their scourges. Admittedly, the Furies are more goddesses that outright monsters, but given that many stories depicted them as having dog's heads, snakes for hair, back wings and "coal black bodies", I was willing to make an exception.
10) The Hydra
Perhaps the most famous monster Hercules ever battled, and for good reason — defeating a dragon with nine heads would be memorable on anybody's list of achievements, but a dragon with nine heads who grew two heads every time one was cut off? Oh, and one of the head was immortal, but you didn't know which one? That's impressive. Besides all that, it's breath and blood were both insanely poisonous — even stepping in the tracks it left could kill you. That's insane. Hercules defeated the Hydra as only the second of his 12 Labors, cauterizing the neck stumps of the heads he cut off, before new heads could grow back. The immortal head? He just put a big ass rock on it.
11) The Sphinx
With the body of a lion and the head of a human being, the Sphinx is best known for asking riddles. We tend to forget that if you failed to answer the Sphinx's riddle, it would eat you alive. The Sphinx was more cruel than enigmatic, and in Greek mythology, it also had the wings of an eagle and a serpent for a tail, meaning it was yet another of Typhon and Echidna's horrible children. The Sphinx guarded the city of Thebesm which must have been a big problem for its tourism industry, until Oedipus finally answered its riddle and the Sphinx, in what was one of the greatest cases of sour grapes in history, either threw itself off a cliff or ate itself in bitterness at its defeat.
12) Manticore
The Manticore is very similar to its sibling monster the Sphinx; it has a human head, a lion's body, and wings — bat wings instead of eagle wings, but still. What it lacks in riddle-asking it makes up for in having a scorpion's tail that can shoot poisonous spikes at people, like it's a boss in an ancient Greek videogame of some kind. Most terrifyingly, the Manticore had three rows of teeth in its human-like mouth, which frankly disturbs me to even write. But kids or no, you probably wouldn't want to mess with Echinda; Hesiod described her as "half a nymph with glancing eyes and fair cheeks, and half again a huge snake, great and awful, with speckled skin", who "dies not nor grows old all her days." Especially during family get-togethers.
13) Echidna
Compared to the other monsters on this list, Echidna sounds pretty normal — she was a snake woman. But since she chose Typhon has her lover, she had the distinction of giving birth to the most terrifying, horrible and dangerous monsters in the ancient Greek world, including Cerberus, the Hydra, the Nemelan Lion, Chimera, the Sphinx, several dragons, and even the eagle that Zeus set to eat Prometheus' liver every day in punishment for giving the gift of fire to humanity.
Contact the author at rob@io9.com.