The Flash, Season 4

Warden Gregory Wolfe:
I see you've made a new friend.

Barry:
Yeah. I guess I have.

Wolfe:
I find that interesting. Especially since I was just asked to turn over Inmate Ratchett's case file to the D.A. who represented you for your trial. Coincidence?

Barry:
Not everyone who's in here deserves to be in here.

Wolfe:
You ever heard of the name "Aaron Miller"?

Barry:
No

Wolfe:
Miller was a prisoner here who took to studying at the law library. One day, Mr. Miller decided to take on the appeal of a fellow inmate's case. When he was invariably unsuccessful, that fellow inmate stabbed Mr. Miller to death. Your friend may look like a man, but he's unquestionably a monster. Everyone here is a monster. And if you insist on continuing to bait them, I guarantee you... you will get mauled.