Ace, Clefto and Puppy Poof the Chin Hounds. They are the alter-egos of Cosmo, Wanda and Poof.
They act as Timmy Turner's sidekicks when he wishes himself into the Crimson Chin's comic books as Cleft the Boy Chin Wonder. Their powers are flying and biting. Ace and Clefto once were the target of Nega Chin, who discovered that they were the reason why Timmy was able to win so easily, and he believed he could capture them to their magic.
They look like identical dogs, but in Cosmo, Wanda and Poof's green, pink and purple color scheme respectively, and with capes.
Ace and Clefto first appear in the episode, "The Crimson Chin meets Mighty Mom and Dyno Dad" as Cosmo and Wanda's official superhero forms when they joined Timmy's adventures inside the Crimson Chin comicverse. While acting as these heroes, they could use their magic in plain sight of others, most notably in the episode, "The Big Superhero Wish!" when Nega-Chin tricked Timmy into wishing away all non-villainous heroes' powers.
Puppy Poof was later introduced in the episode, "Chindred Spirits" as Poof's superhero alter-ego, although his abilities and purpose are more or less the same.