The Kerynitis Hind was a deer that was both sacred to Artemis and incredibly fast.
One of the stories of the capture of the Hind simply tells of Artemis capturing the Kerynitis Hind while hunting. She captures five hinds, using four of them to pull her chariot. These four hinds became known as the Elaphoi Khrysokeroi. The fifth deer escapes, and Artemis grants the animal protection, and it became sacred to the goddess.
Capturing the Hind was Herakles' the third task. Hera hoped that forcing Herakles to capture animal sacred to Artemis might drive a wedge between them. Artemis in fact did approach Herakles when he began hunting it. Herakles however promised he would not severely wound or kill the animal and he would release it, so Artemis let him continue. Herakles spent an entire year chasing the Hind until finally he shot one of his arrows (a non-poisonous one) which went clear through two of the legs. His shot was so masterful it did not even draw blood. The hind was however immobilized and Herakles showed the deer as proof of its capture and then made good on his promise to Artemis