Wandering Lost Dog is a AU version of The Annoying Dog. He is the only citizen of Outworld whose backstory is unknown. he functions as Wanderer's Dog, and looks exactly like Annoying Dog, other than a purple collar.
Wandering Toriel- his favorite person, she finds him ridiculously annoying
WanderBerry- Another one of his favorite people.
Despite being a dog, unable to speak, and unable to see, he can some how use a tablet to edit reality. Also, he can teleport between worlds with a SEND command.