Here are 5 of the weirdest music trends of the year, according to Spotify Wrapped

• Spotify just dropped Wrapped, its annual roundup of top-streamed songs, artists, genres, and podcasts.
• The report highlighted some particularly bizarre trends this year, including playlists for plants.

It's that time of year again, when Spotify listeners flock to the app to pore over their most-streamed songs and top artists.

The music streamer released Spotify Wrapped on Wednesday, its annual report featuring personalized roundups of top songs, artists, genres, and podcasts, as well as wider analyses of trends across its millions of listeners. While findings like the world's most-streamed artists — which included Bad Bunny, Taylor Swift, and BTS in 2021 — may be unsurprising, other trends are raising an eyebrow or two.

From songs for plants to alien-inspired playlists, here are some of the most bizarre music trends this year, based on findings from Spotify.

Sea shanties topped the charts

After sea shanties went viral on TikTok earlier this year, Spotify listeners were quick to compile playlists with their favorite tunes — compiling more than 187,000 sea shanty-related playlists, to be exact.

The shanty "Wellerman," by British folk musical group, The Longest Johns, was one of the most popular shanties added by listeners, according to Spotify.

"Sea shanty Tok" quickly became a massive trend online as TikTok users around the world starting singing the seafaring songs in videos. Although some have said that "Wellerman" is not actually a shanty, the trend brought awareness to the history of the genre, which consists of folks songs traditionally performed by fishermen, whalers, and sailors.

Listeners made playlists for The Final Frontier ...

Spotify users generated more than 25.5 million playlists related to aliens, UFOs, and space during the period from March to May 2021, according to Spotify.

The rise of the playlists came as aliens appeared frequently in the news this spring, including a "60 Minutes" segment in which US Navy pilots discussed about their alleged encounters with UFOs, as well as an investigative piece about UFOs and the Pentagon written by The New Yorker's Gideon Lewis-Kraus.

The rise of the playlists also reflected the continued popularity of science fiction movies and television shows in recent years, especially as viewers looked for escapist content during the pandemic.

And while a government report was released in June dismissing the likelihood of aliens, some things can still not be explained.

... and also for their plants.

Followers of the Spotify original playlist, "Music for Plants," grew by 1,400% in 2021 as listeners looked to flex their green thumbs during the pandemic. Meanwhile, Spotify users themselves created more than 2.9 million playlists related to plants and gardening this year, according to data from the app.

Popular plant-related songs featured on these playlists included "Ivy" by Frank Ocean and "Garden (Say It Like Day)" by SZA.

Astrology-themed playlists hit the charts

As astrology continues to explode in popularity, it was reflected in music and audio preferences in 2021, according to Spotify.

Astrology became a billion-dollar industry during the pandemic, and as a result, Spotify users created over 10 million horoscope and astrology-themed playlists.

Spotify also launched a more personalized listening experience this year called Only You. The feature, which launched in June, creates "audio birth charts" based on user listening habits and curates statistics for users of the streaming app to view and share.

Vaccine playlists became a trend this year

As coronavirus vaccines became widely available to the public earlier this year, Spotify users decided to get creative and create playlists inspired by the shots, according to the app.

Spotify listeners streamed more than 42 million vaccine-related playlists this year, featuring songs like Pat Benatar's "Hit Me With Your Best Shot" and "The Cure" by Lady Gaga.