"Night Prowler" is the final track on AC/DC's album Highway to Hell. It is known among other AC/DC songs for its slow blues rhythm, ominous lyrics, as well as its controversy stemming from its association with the Richard Ramirez serial killings in 1985.
The song is in a 12/8 time signature. It has been documented and verified that Mutt Lange slowed the track down by 5.25% (almost half a step) which accounts for the guitars being slightly out of (normal) tune. It is not known why he did this. "Highway to Hell" was also slowed down by 3.33%.
In June 1985, a highly publicized murder case began revolving around Richard Ramírez, who was responsible for more than a dozen brutal killings as well as attempted murders and rapes in Los Angeles. Nicknamed the "Night Stalker," Ramírez was a fan of AC/DC, particularly the song "Night Prowler". Police also claimed that Ramírez was wearing an AC/DC shirt and left an AC/DC hat at one of his crime scenes. During the trial, Ramírez shouted "Hail Satan!" and showed off the pentagram carved into his palm. The incident brought extremely bad publicity to the band, whose concerts and albums were suddenly campaigned against by parents in Los Angeles County. On VH1's Behind the Music on AC/DC, the band claimed that while the song had taken on a murderous connotation by Ramírez, it is actually about a boy sneaking into his girlfriend's bedroom at night. The song, however, does contain lines such as "You don't feel the steel/Till it's hanging out your back... as you lie there naked, like a body in a tomb".
Bon Scott was an avid fan of Robin Williams, and he ended the song with one of Williams' famous catchphrases: "Shazbot, Nanu Nanu!" These originated from the extraterrestrial character 'Mork' from 'Mork & Mindy': 'Shazbot' was an all-purpose vulgar exclamation, and 'Nanu Nanu' was a greeting/salute Mork used at the end of his transmissions to his home planet. Coincidentally, this sign off at the end of the album is the last known recording of Scott. He died in February 1980.