Bow-Wow

Bow-Wows (ワンワン) are recurring creatures in the Legend of Zelda series. They are spherical, toothed animals that lunge at their enemies to attack. Depending on the game, Bow-Wows serve as both antagonists and protagonists. Interestingly, Bow-Wows act very similarly to domesticated dogs. The "chain" that is a part of their bodies serve as a sort of leash for the holder. They also occasionally emit sounds similar to a dog's bark.

The Legend of Zelda: A Link to the Past
Bow-Wows are enemies. They appear in Turtle Rock and are invulnerable to attacks. Their primary attack is to swiftly lunge at Link.

The Legend of Zelda: Link's Awakening
Three Bow-Wows are the pets of Madam MeowMeow. After Link completes the first dungeon, Tail Cave, one Bow-Wow is stolen by a pack of Moblins and must be rescued from the Moblin Cave in order to continue onward to the Bottle Grotto. Once rescued, Link can utilize its chain as a leash, and Bow-Wow will attack all that oppose Link. Link can use this effect to destroy the Goponga Flower surrounding the Bottle Grotto. Link must return Bow-Wow to Madame MeowMeow before he can complete the Kanalet Castle side quest, as Richard will not speak to him and Kiki will not accept the Bananas Link offers him until he does so.

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.

The Legend of Zelda: Four Swords
One Bow-Wow appears in Vaati's Palace as an item. Bow-Wow gives one Link an advantage over the others because he can attack enemies and allies. For the latter, he steals Rupees.

The Legend of Zelda: Four Swords Adventures
One Bow-Wow appears to the north of Kakariko Village as an enemy.

Origin
Bow-Wows are likely a renamed version of the famous Mario series enemy, Chain Chomps.

Gallery
gallery> File:Bow-Wow (Four Swords).png|Artwork of Bow-Wow from ''Four Swords