Lyric discussion by 7Endless7 

Cover art for Rusty lyrics by Dismemberment Plan, The

This song reminds me of the time I was a kid, swinging and jumping from the swing. I miscalculated my final launch & hit the ground hard. Broke my arm in 5 places.

To me, (on a riff from a previous post,) the song is, in fact, about a loss of innocence. The protagonist is at a childhood party, leaps from a swing set and ends up face down in the dirt. ("My nails encrusted in brown") While all the other kids are playing, he's in agony and comes to the inevitable realization that he's not invincible. Life hurts, a lot.