Songfacts®:

• "Teeth" is about a toxic relationship with a girl who has multiple personalities.
  
  Fight so dirty, but your love so sweet
  Talk so pretty, but your heart got teeth
  Late night devil, put your hands on me
  And never, never, never ever let go
  
  5 Seconds of Summer's single "Youngblood" has a similar theme. Both are about a romance that veers between lust and lament.
• "Teeth" came about after the band had been writing for a month or two and were searching for something that was a step further than "Youngblood." Said frontman Luke Hemmings: "It was a tumultuous time in my life and the lyrics in the song definitely reflect that. It speaks lyrically about a trying time in my current relationship."
• The bass-heavy track was written by 5 Seconds' Luke Hemmings and Ashton Irwin with Ali Tamposi, Ryan Tedder, Andrew Watt and Louis Bell; Watt and Bell produced the song as well. Tamposi, Tedder, Watt and Bell also penned 5 Seconds of Summer's previous single, "Easier," with the band.
• Both "Easier" and "Teeth" have similar, brooding vibes, with "Teeth" venturing further into industrial territory. Bassist Calum Hood told Billboard they found themselves channeling one of their fellow Aussie bands.
  
  "With 'Teeth,' I knew it was something that we hadn't discovered yet within the band," he said. "It reminds me of like - as weird as it sounds - AC/DC in terms of the pulse and energy. It's really a special thing for me because it means that we're almost connecting with the roots of the band in a modernistic way."
• "Teeth" features Tom Morello of Rage Against the Machine Morello playing guitar throughout the track.
• The song features on the third season soundtrack of the Netflix series 13 Reasons Why.
• The song is accompanied by a dark, creepy video directed by Thibaut Duverneix, who also shot Tierra Whack's visual album Whack World. We see each band member getting operated on; after being knocked unconscious, each journeys into a dark and scary hellscape.
• Hemmings told Billboard the song came together very quickly. "It was just a bass line. And then [we] worked on the melody and then the lyrics came after. It was very, very, very simple... It was just one of those ideas that really stuck out and we held on to, and we ran with it on the day."