Lyric discussion by MusicMan55410203 

Cover art for Halloween lyrics by Gaslight Anthem, The

I think he's straight up talking about his own depression. First half of the song is him dealing with his depression, and this particular time it's at a Halloween party. So he dresses like a corpse in a suit.

And he sees similar hurt in one particular person, but isn't sure but wants to "keep it coming"

My Interpretation