"Polly" by Nirvana is one of the darkest songs in the band's catalog. Originally called "Cracker" and "Hitchhiker," it was written after Kurt Cobain read about a real-life rape.
In 1987, Gerald Arthur Friend abducted a 14-year-old girl in Tacoma, Washington. During the time he held her captive, he repeatedly raped her, using a blowtorch and other objects. Eventually, she was freed by jumping from his truck at a gas station. He was later convicted for the crime and jailed for life.
After reading the newspaper story, Kurt Cobain took on the persona of convicted rapist Gerald Friend. Then, he wrote a song about the event, telling the story from the point of view of the kidnapper.
"Polly" has a repetitive sequence and is very dark. It's also full of cruel lyrics. For instance, in the chorus, a kidnapper calls his victim a parrot. This contrasts with the more pop-ish music heard in the rest of the song.
Ultimately, Cobain used the publicity surrounding the song to voice his frustration with society's treatment of sexual assault victims. Several other artists have done the same. Throughout his career, Cobain challenged the archetypal white male rock star and supported the LGBTQ community.
Even though the song's lyrics are disturbing, many listeners find the lyrics of "Polly" to be relevant. Nirvana has supported a number of concerts for rape victims. Their last live performance of "Polly" was at Terminal 1 in Munich, Germany, on March 1, 1994.