Yarrr is Maxwell'spirate brother. He's the 3rd brother to arrive at Edwin's Farm, riding in his pirate ship that mysteriously works on land. He gives Maxwell directions to The Listy Colon and its surrounding areas. Suddenly his ship is attacked by a cannonball from an enemy ship and both Maxwell and Yarrr, headed for The Listy Colon, have to stop the enemy ship.
Yarrr's Rooster Helmet looks like a pirate's hat and a beard. He wears a red coat, black boots and like the stereotypical image of a pirate he has a hook for a hand and an eyepatch.
How to Unlock
Yarrr and Maxwell are under attack. Assist Yarrr by supplying him with more ammo. Give Yarrr a Cannonball or a Bullet. Even though these two work, nearly any object works as ammo, including people and other NPCs.
Yarrr steals Shadow's sword if Shadow is near. This may be yet another reference to the Pirates vs. Ninjas debate.
He is a reference to Blackbeard.
His name is likely a reference to the stereotype of pirates saying "Yar".
Yarrr will attack the Lily that spawns in the Batcave in Scribblenauts Unmasked. Note that he will not attack Lily if spawned using the "@" method