Pushme Pullyu

The Pushme Pullyu resembles a a two-headed horse and is found beneath the Palace of Blackthorn in Ultima VI.

The two heads speak in riddles at a fork in the tunnel, and from its confusing words, the Avatar must decide which is the safest path to travel.

Blackthorn's Castle has been taken over by the mad mage Sutek at the time the Avatar meets this creature, and many of Sutek's experiments have two heads. It's possible that the Pushme Pullyu was created by him.

Trivia

 * The "Pushme Pullyu" was taken from a Dr. Dolittle story, identified as a two-headed llama-type creature.