Yapper is a character appearing in Layton's Mystery Journey: Katrielle and the Millionaires' Conspiracy. He serves a similar role to the Hamster, the rabbits and Hazel.
Biography[]
Appearance[]
Yapper is a large dog with small black eyes, brown fur, a darker shade of brown on his muzzle and ears, and a white belly.
Personality[]
He is very kind and enjoys the life of being a street dog.
Plot[]

Case 4: Pet Pandemonium[]
Yapper tells Sherl that the White Cat woke him up after stepping on his tail. Angered, he barked at the feline and made him run away to the Tower Bridge.
Case 6: An Unexpected Windfall[]
When Katrielle and co. are in pursuit of Shadee, he tells Sherl that he saw him (Shadee) head down to the Wharf.
Case 7: Ratman Returns[]
When Seán Butchin is inquired about his sightings of/relations to Ratman, he explains that one time Yapper had stolen his sandwich, and Ratman had to go get it back for him.
Yapper later brings this up again with Sherl, where he states that Ratman had 'showed up and ruined everything'.
Spoilers end here
Profile[]

A stray that roams the London streets, from the river to Bowlyn Hill. Nobody realizes the in-depth conversations he has on a daily basis with Sherl.