1.Crookshanks was the Potters pet!

During The Deadly Hallows Harry finds an old letter from his mother at Grimmauld Place, she mentions that they have a cat that Harry almost ran over with his toy broomstick.

When Hermione adopts Crookshanks from Diagon Alley years later, the pet shop owner mentions that he has been there a long time. And let's face it, if any cat could withstand an attack by the most evil wizard in creation, it would totally be Crookshanks.

Still not convinced? Then explain how Crookshanks knew immediately to hate Scabbers…but trust Sirius in his dog form. Maybe because the cat was used to seeing them around years ago? The cat was the one who helped expose Peter Pettigrew (when he was disguised as that rat Scabbers) and acted as Sirius Black's shield when Harry was planning to kill him.

2. Crookshanks is Regulus Black

*I know the books stated he died in the lake of inferi, but it’s still an awesome theory*

The Black family is known to name their children after constillations. Sirius is known as the dog star and Regulus is a star in the constellation Leo! Aha Leo, a big cat!

I think it's no coincidence that Crookshanks is only introduced in the books once Sirius Black escapes in Prisoner of Azkaban? Perhaps, it is then that Regulus decided to seize the opportunity to make his way into Hogwarts. After all, he knew his brother would need his help finding a way to defeat Voldemort and Hermione would be the perfect vehicle!

The next indicator is that Sirius reveals to Harry that he has learned to communicate with Crookshanks. Now, this is just bizarre if the cat was a normal critter because even an Animagus learning to talking to random pets seems a little far-fetched. But if Crookshanks was an animagus.

And fore mentioned argument stating the cat seemed to know both Scabbers the rat and his wicked ways and Sirius in dog form could fit in this theory too!

So what do you think? Is this part kitty, part kneazle more than just a pet. Let us know!