Shamus O'Malley is a native of Ireland and a crewman/friend of the Marceline Guild. This pirate loves his homeland so much that during the time of St. Patrick's Day, he plays a massive prank to turn the water of the Caribbean green! He accomplishes this by stealing a shipload of the East India Trading Company's green dye and dumping it overboard as he sails.

Also, on St. Patrick's Day, if a pirate should meet Shamus, he happily gives them a Redeem Code for 500 free gold!

Shamus appears to be wearing a Lucky Long Coat from the Emerald Duelist outfit.

Shamus is played by a GM and only appears once a year for this special event, though the waters remain green for a number of days.