25 các điểm thưởng for solving my Harry Potter riddle!!! Up for the challenge?

I asked this riddle on the Harry Potter diễn đàn and not many people seemed to be interested(although it's still on there, if bạn want to try)
so..... I'm posting it here to in hopes that someone will finally solve it!!!!!

I upgraded the prize for the 1st correct answer from 15 to 25 các điểm thưởng and me as a người hâm mộ if I'm not already!! If I see many people struggling I will give a hint!!!!


"You saw some of my kind before,
but I was the first bạn heard.
I was used to escape trouble (though it led to much more)
the squib would've had bạn cornered
but I let bạn through the door."

Can be anything of the Harry Potter world - keep your mind open!!!!