Mangum wrote surreal and opaque lyrics that covered a wide range of topics, including love, spirituality, nostalgia, sex, and loneliness.

In 1996, he worked with childhood friend Robert Schneider to record the album On Avery Island, which received modest reviews and sold around 5,000 copies.

Mangum recruited musicians Julian Koster, Jeremy Barnes, and Scott Spillane for the band's second album, In the Aeroplane Over the Sea.

This negatively affected Mangum, whose mental health began to deteriorate; he did not want to continue touring and Neutral Milk Hotel went on hiatus shortly after.

Many indie rock groups such as Arcade Fire and the Decemberists were influenced by Neutral Milk Hotel's eclectic music and earnest lyrics.

[1] Early Milk recordings, such as Invent Yourself a Shortcake and Beauty, were shared between Mangum and his friends Robert Schneider, Bill Doss, and Will Cullen Hart.

[2] The four friends branded these homemade cassette tapes with an imaginary record label, Elephant 6, which eventually grew into a loose musical collective.

[9] The members of the Apples in Stereo wanted to sign with SpinART Records, and met with their legal representative, Brian McPherson, in Los Angeles.

[20] Kurt Wolff of the Houston Chronicle described listening to the music as "a trippy experience," and ultimately called the album "a fresh, exciting standout".

[21] The British publication NME wrote: "Neutral Milk Hotel can convert miserable-as-sin introspection into folky mantras that bore into your skull like a well-aimed power drill.

[29] The On Avery Island tour generated enough money for the band members to afford to move to Athens, where a large group of Elephant 6 musicians were living.

[40] Rob Brunner of Entertainment Weekly praised the unique instrumentation and "bouncy pop melodies", but described some of the songs as "lifeless acoustic warblers.

"[42] A more negative review came from Ben Ratliff of Rolling Stone, who felt the heavy layer of distortion masked the absence of decent melodies.

"[48] The band members often could not afford lodgings, and sometimes asked people in the audience if they could spend the night at their house, not realizing the homeowner was in fact terrified of them.

[50] The album, and by extension Neutral Milk Hotel, became common fixtures on online message boards, and early music websites like Pitchfork gave the band an increased level of promotion.

Some were angry, and accused Mangum of being selfish, and others wrote hoax blog posts giving fake details of upcoming tours and other false information.

[52] The speculation and online discussions raised the profile of the band, to the point that Neutral Milk Hotel and, in particular, In the Aeroplane Over the Sea gained a cult following and converted Mangum into a larger-than-life figure.

"[61] Journalist Mark Richardson attempted to explain In the Aeroplane Over the Sea's rise in popularity: "Because [Mangum] was inaccessible, there was no outlet for connection other than the record itself and other fans who shared a passion.

"[62] In the Aeroplane Over the Sea's critical standing rose tremendously in the years after its release, which journalist Luke Winkie attributes to the cult following.

[57] Polygon writer Garrett Martin noted how fans of the album were "incredibly passionate", recording covers for YouTube, writing poetry, and forming tribute bands.

[66] During this time, Mangum curated a box set of Neutral Milk Hotel material, which included an extended play of unreleased songs titled Ferris Wheel on Fire.

[84] Critic Chris DeVille offers similar commentary, writing: "On the musical axis, Neutral Milk Hotel veered from piercingly intimate psychedelic campfire sing-alongs to full-band segments that barreled ahead with haphazard grace.

[87] Critic Jim DeRogatis describes Mangum's lyrics as surreal and opaque, and notes that they feature a stream of consciousness style of songwriting.

[89] Biographer Kim Cooper cites the song "King of Carrot Flowers, Pt.1" as an example of this style of songwriting; although the lyrics are about childhood fantasies, there are references to sexual awakenings, domestic violence, religious fanaticism, and tarot card readings.

[94] A central lyrical topic in In the Aeroplane Over the Sea is the life of Anne Frank, a teenage girl who died in a Nazi concentration camp.

[107] Elephant 6 biographer Adam Clair notes that Mangum's unexplained absence made him more notable than when he was an active member of the music industry.

[108] He actively avoided giving interviews, and as a result, music publications began to write clickbait-esque articles in which they would attempt to explain his disappearance with little to no substantive evidence.

[110] While many groups focused on the theme of detached irony, Neutral Milk Hotel's abrasive and overtly emotional lyrics struck a chord with social outcasts.

[111] Groups influenced by Neutral Milk Hotel include Arcade Fire and the Decemberists, both of whom create psychedelic-folk inspired music with non-traditional instruments.

[112] Neutral Milk Hotel also influenced bands like AJJ,[113] Beirut, Bright Eyes, The Lumineers,[114] Okkervil River,[37] and Pwr Bttm,[115] as well as artists like Melanie Martinez,[116] Kesha,[117] and Amanda Palmer.