There is a part in Harry Potter POA when Harry's in the Hogsmeade room and he seems to talk to himself in the mirror. The mirror replies back to him. Can't remember the quote but does anyone else know anything about this? The book didn't explain anything regarding it.

I think you're talking about the Leaky Cauldron. If I remember correctly, the mirror is an empty canvas where Phineas Nigellus lived. Well, one of the portraits of himself around London. Harry made a comment about his looks and Phineas replied back. It was only later that Harry found out who the resident of the "mirror" was. If you don't remember, Phineas was Sirius' relative.

I think this answers your question.

Yeah i think it might've been Leaky Cauldron. Couldn't remember the place lol

So it was Phineas huh? I thought it was a reflection of harry talking back.

Thanks anyway

No, it was Phineas. I think this was explained in the book, but I haven't read it in a while so I can't be 100% sure.

Since I answered your question, I'm closing this topic.