Crookshanks.

[GodrictheGriffon]

You know the letter that Harry found in Sirius' room? and how it mentioned a cat and Harry was wondering what happened to it? Well, I pictured teh cat as a black one just because that's the stereo-typical cat for witches and wizards. But what if the cat was ginger, with a squashed face, and, part kneazle? What if teh Potter's cat was a Crookshanks. That would explain how he knew Sirius and why Sirius trusted him.
Or the cat might have been Proffessor McGonagall.

[DucksRMagical]

I doubt the cat was Professor McGonagall. She would have been teaching at Hogwarts!

I also don't think Crookshanks was their cat. I would think that that would have been explained by the end of the series.

[youknowwho]

That would also make Crookshanks at least 17 years old yet he still seems young and active.

[noris]

Pets from the wizarding world seem 2 live longer and have abilities of some sort. Remember when Ron went to the pet shop 2 get something for Scabbers.

[Ms. Elsewhere]

Wild theory! I don't even remember the mention of the Potter's cat! (must read my books again)

I wonder too.... what happened to Crookshanks? He never got enough of a mention in my opinion.

[teyannanecole]

The cat being Crookshanks would explain why he was always so hostile toward Scabbers. But when questioned Jo has explained that heis just a really smart cat and his animal instincts were lettig him know that there was a traitor in the mist.

[Alice5130]

Did Hermiony leave Crookshanks with her parents when she, Ron, and Harry left Hogwards? I'm too lazy to look it up, and don't have the time to re-read the books right now. At least, not until my midterms are over with. 6 more weeks X3