Chain Chomp

Bow-Wow (ワンワン, Wanwan) is a version of the Chain Chomp from Super Mario Bros. It is found as an enemy in A Link To The Past, as an ally in Link's Awakening, and as both an ally and enemy in Four Swords.

A Link to the Past
In A Link to the Past, Bow-Wows can be found as enemies in Turtle Rock and the Palace of the Four Sword. They are invulnerable to all forms of attack and yield an incredible amount of damage. In Turtle Rock, there are only two Bow-Wows found in one room.

Link's Awakening
In Link's Awakening, Madam MeowMeow is the owner of a docile Bow-Wow. Both Bow-Wow and his owner live in Mabe Village. After completing the Tail Cave dungeon, Bow-Bow is kidnapped by a gang of Moblins. Link rescues him and brings him back to Madam MeowMeow, who then asks Link to take her pet on a walk. Bow-Wow can then be used to eat the otherwise-impenetrable Goponga Flowers blocking the entrance to the game's second dungeon, Bottle Grotto. Although Bow-Wow can take care of most enemies for Link, he cannot be taken into dungeons.

Two more pet Chain Chomps are owned by Madam MeowMeow. A smaller one is inside her house and a second is in a doghouse nearby. The second Chain Chomp is quite obviously a female, with a strong desire for jewelry and other such accessories. She helps Link with the trading sequence: If he gives her the Bow, she'll give him the Can of Dog Food.

In Link's Awakening DX, a picture can be taken with Bow-Wow.

Four Swords
Bow-Wow can be obtained as a player upgrade. While Bow-Wow is your 'pet' it will not attack you. It will attack enemies and other Links within its reach. Like all items in an area, Bow-Wow is not a permanent item.