The Three-Headed Monkey was a mythical monkey that had three heads. It could be found on Monkey Island. One of Guybrush Threepwood's often repeated catchphrases is "Look behind you, a three headed monkey!" His usual reason for stating the line would be to momentarily distract someone in order to steal one of their possessions.
Threepwood said the line slightly differently while duelling Morgan LeFlay. "Look behind you, a three headed sea chimp."
The Secret of Monkey Island
Sometimes when Guybrush is defeated in an Insult Sword Fighting duel, he would also shout, "Look, a three-headed monkey!"
After you free Otis from Mêlée Island Prison without mentioning the capture of Elaine Marley beforehand, he'll consinder of joing Guybrush's crew before saying the line and then runs away when he's distracted. When noticing that Otis is gone he remarked that he couldn't believe he fell for that trick but admited it was a good one.
When caught by the cannibals in their village, Threepwood may say the line again in order to unsuccessfully make an escape. Ironically a three headed monkey would reveal itself behind them right after, but they won't fall for it a second time.
When Threepwood gives the cannibals the voodoo root which would be used to defeat LeChuck, he is met by the three headed monkey while the cannibals are away, preparing the ghost zapping mixture.
When asked by the troll for something that was distracting but of no real worth to anyone, Threepwood could suggest 'A monkey leash with three collars'.
Monkey Island 2: LeChuck's Revenge
The three headed monkey is mentioned in one of the books in the Phatt City Library, where it speculates that the creature was the son of the Loch Ness Monster.
Threepwood may also use his line on the Phatt Island Guard and a number of characters.
The Curse of Monkey Island
An animatronic prop of the three headed monkey is seen in the first feature on the Big Whoop Rollercoaster.
Escape from Monkey Island
The three-headed monkey makes minor appearances in the game. He appears in Herman Toothrot's flashback.
If Threepwood waits around Monkey Town (formerly the cannibal's village in the first game), the three headed monkey can be spotted in one of the huts.
- The line 'Look behind you, a three headed monkey!' has appeared as a homage in a number of other LucasArts titles. E.g. in Day of the Tentacle the fused characters can say it to a purple tentacle to get the response "The only three headed monkey I see is standing in front of me."