These animals possessed some fantastic super-natural attributes and abilities which made them extraordinary and myth worthy.
Amphisbaena - an ant-eating serpent with two heads, one at each end of the body. It was also called the Mother of ants.
Balius and Xanthus - the immortal horses of Achilles who took them to draw his chariot in the Trojan war. The horses were given to Achilles by Peleus, who had previously received them as a marriage gift from Poseidon.
Calydonian Boar - a gigantic boar sent by Artemis to ravage Calydon, after the king Oineus forgot to donate her offerings. It was later slain in Calydonian boar hunt by king's son Meleager with the help of Atalanta who drew the first blood.
Carcinus - a giant crab which fought Heracles along the Hydra in his second labor. The hero crashed it with his foot.
Ceryneian Hind - an enormous deer which was sacred to Artemis. Heracles was sent by Eurystheus to retrieve it in one of his labours.
Chrysomallus - a flying, talking, golden-fleeced ram which took prince Phryxus to Colchis and instructed him to sacrifice it to Zeus and place the golden fleece on the holy tree.
Erymanthian Boar - a gigantic boar which Heracles was sent to retrieve in one of his labours. The hero lured the boar into deep snow, immobilizing it. Then he tied the boar and carried it back to Mycenae
Laelaps - a dog destined never to fail catching its prey.
Mares of Diomedes - four man-eating horses that belonged to the giant Diomedes. Heracles captured them in one of his labors but faced a cruel reality when the horses ate his favoured companion Abderus. Therefore, in revenge, Heracles left Diomedes to be eaten by his own horses.
Nemean Lion - a gigantic lion with impenetrable skin. It was strangled by Heracles in his first labor, when he almost gave up. He wanted to bring his skin as proof but coudln't get hands on it until being hinted by Athena how to deal with it.
Phoenix - a golden bird that could regenerate itself by bursting into flames and rising from the ashes.
Stymphalian Birds - man-eating immortal birds with beaks of bronze and sharp metallic feathers which they could launch at their victims. It is said that these birds were pets of Ares. They were encountered by Heracles and the Argonauts.
Teumessian fox - a gigantic fox destined never to be caught. Allegedly, it was sent by the gods to prey upon the children of Thebes.