1. Song by My Chemical Romance, off of their first album, "I Brought You My Bullets, You Brought Me Your Love."
2. Falling, usually headfirst, in which the person is seriously injured or just really shaken up (halos, in this sense, being "death" or "near-death").
1. person one: "wow, i love my chemical romance, 'headfirst for halos' is definitely their best song!"
person two: "i know, right?"
2. person one: "hey man, did you hear about nick?"
person two: "no, what happened?"
person one: "aww, he totally went headfirst for halos; he fell through a window. he's in the hospital, but he's gonna be ok."
or:
person one: *doesn't watch where they are going* oh shit, why didn't you warn me about those stairs? i almost went headfirst for halos there."
Similar to catfishing, this is when someone only shows themselves from the chin up, to make themselves look better than what they are, sometimes used with a heavy filter of some sort.
Person 1: Ayy check this shorty out.
Person 2: Damn she kinda cute, what other photos she got Person 1: Oh wait never mind, I just seen the player build, she’s headfishing.