Where the princesses are
The Merrymen travel along with Robin Hood in with their goal to kidnap princesses.
They appear in Shrek when Shrek and Donkey just escaped from the castle and saved princess Fiona and were walking in the forest. Suddenly Robin Hood appeared along with his Merrymen in attempt to kidnap Fiona. When they have beaten Shrek and Donkey, Fiona starts attacking them until they all are KO'd. After their defeat they quickly escape.
They later appear in Shrek's Karaoke Dance Party singing the song YMCA.