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.

Runes of Virtue
A strange two-headed horse named Klip Klop resides within the Cavern of Deceit in Runes of Virtue, and it is very likely this creature represents Pushme Pullyu from Ultima VI. This strange beast presents a riddle similar to that offered by Sutek's strange creation, with Klip stating one head always lies, while Klop offers directions through the maze. If the hero chooses to ignore Klop's advice, both routes will be accessible.

Trivia

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