Bow-Wow

The Bow-Wow (ワンワン Wan-Wan) is a spherical, toothed animal which lunges at it's enemies, and is no doubt a reference to the famous enemy in the Super Mario Bros. series, Chain Chomp. It has appeared as both an enemy and a protagonist, in A Link to the Past and Four Sword Adventures being a foe, and Link's Awakening being a counterpart.

Link's Awakening
The main Bow-Wow (named "Bow-Wow") is owned by the benevolent woman in Mabe Village, Madam MeowMeow. After Link completes the first dungeon, Tail Cave, Bow-Wow is stolen by a pack of Moblins and must be rescued in order to embark on his journey towards Bottle Grotto. Once rescued, Link can utilize his chain as a leash, and Bow Wow will then attack all that oppose Link, in result making him virtually invulnerable for the time being.

Other Bow-Wows in the game include a few friendly, miniature yet identical creatures that appear unchained in a couple of buildings. One of these, Mini-Bow Wow, is portrayed as a female who, unusually, can speak and sports a ribbon in her hair. She gives Link a can of dog food in exchange for the ribbon that she wears.