You must time travel like the show.

Search engines are very informative.....;)

Hmmmm, when I first saw him I thought he was the prison dog. But with these photos, I see that that's just a dog.

There's only 1 dog in the phase files.
That same dog appears in the jail cell right next to you, when you create a new pirate.
The recent video from Disney "Get Connected" thing, specifically talked about this dog - the dog that is in the original ride. "Q: Are there any hidden Easter Eggs? A: One our favorite four-legged canine friends here in the ride, makes an appearance on Outcast Island. But ya gotta look really hard for him, 'cuz he's pretty well hidden."

Dude! At the beggining of the game at the jail you can see him with the keys in one of the cells!

dude there are 2 dogs in the phase files