This song is about a Tasmanian Devil's unrequited love for a girl called Adeline.

Ooh, my Adeline, ooh
Down in Tasmania
Where the devil's jaws are far too weak
To tear you away
Ooh, I wish you well

Alt-J tweeted an explanation of the song when it was made available on May 24, 2017: "A Tasmanian devil falls in love with a woman as he watches her swim. Enjoy."

Speaking on Zane Lowe's Beats 1 show, keyboardist Gus Unger-Hamilton revealed that ideas for the track originated when the band was on tour.

"It initially started to be written in Australia, and was one of the ones we'd do in soundcheck quite a lot - just like playing with little bits of it and trying it out, trying to remember what was good with recordings and voice memos," Unger-Hamilton said. "Then we'd come back to it time and time again, and when we came back to the UK to make album number three, we knew 'Adeline' was going to be a song that would be on that record. So we got together, unwrapped all of our ideas and looked at what we had - and then we put it all together."

The song incorporates an adaptation of a melody from Hans Zimmer's soundtrack to The Thin Red Line.

The strings are courtesy of the London Metropolitan Orchestra. They also played on the Relaxer track "3WW."

Alt-J often incorporate watery images into their lyrics. Relaxer's lead single "In Cold Blood", for instance, is about a pool party that takes a dark turn.

Fun Fact: The Tasmanian Devil, which is only found in Tasmania, is the largest carnivorous marsupial. According to 2005 study, Tasmanian devils have the most powerful bite relative to their body mass of any carnivore on this planet.

My Adeline was swimming
Sweet Adeline was singing
To the tune of Royal Canal

This lyric is a reference to the Irish song "The Auld Triangle," which was written by Brendan Behan as part of the play The Quare Fellow and was popularized by The Dubliners. It was also recorded and released by The Clancy Brothers & Tommy Makem under the name, "Royal Canal." Alt-J explained to NPR that it "is a favorite song of ours to sing when we are traveling and/or drinking."