A song widely suspected of being generated by AI has climbed to number 58 on the Billboard Hot 100. "Rubberz," credited to Los Angeles rapper Fenix Flexin of Shoreline Mafia, is the first mainstream chart hit to face sustained public accusations that the recording itself — not just the promotional art around it — was produced by a generative model. Fenix has denied the allegations. He has not released the raw session files that would settle the question.
The circumstantial case is unusually thick. Multiple AI image detectors flagged the single's cover art and a celebratory social post as AI-generated with over 97 percent certainty. Feeding the lyrics into Claude and Gemini produced flags for AI authorship on both. Five AI music detectors run against the audio returned a 20 to 30 percent probability that the track is AI or AI-assisted — inconclusive on its own, but notable given how quickly music-generation models are outrunning the detectors built to catch them.
The audio itself is the strongest tell. Charlie Harding, a songwriter and co-host of the Switched on Pop podcast, walked through the specific artifacts for The Verge: brittle hi-hats, chorus vocals with the character of a low-bitrate MP3, and reverb tails that cut off unnaturally. He tied the degradation directly to training-data quality — a diagnostic argument, not a vibes-based one.
“Ghostly backing vocals duck in and out unexpectedly. The drum reverb is full of unnatural digital artifacting reminiscent of a 64kbps MP3 downloaded off of Napster. Because most generative AI companies have trained their model on low-quality MP3s of unlicensed copyrighted material.”— Charlie Harding, Songwriter and co-host of Switched on Pop
Key facts
- 01'Rubberz' by Fenix Flexin has climbed to number 58 on the Billboard Hot 100 despite widespread AI-generation allegations.
- 02Multiple AI image detectors flagged the single's cover art and a promo post as AI-generated with over 97 percent certainty.
- 03Five AI music detectors gave the track a 20 to 30 percent probability of being AI or AI-assisted — inconclusive but not clean.
- 04Songwriter Charlie Harding compared the audio artifacting to a 64kbps MP3, a signature of models trained on low-bitrate scraped audio.
- 05Fenix has denied the accusations and posted alleged Pro Tools session files, but has not released the raw project files.
The stylistic pivot is also part of the suspicion. Fenix built his career on trap-influenced West Coast rap. "Rubberz" is an '80s UK synth pop pastiche, with a vocal melody indebted to Morrissey and a fake British accent Fenix cannot reproduce live. Artists are allowed to evolve. They are not usually allowed to evolve into an entirely different singer between the studio and the stage.
The lyrics read the way generative models write when pushed to rhyme. The scheme is a rigid AA, BB with no internal rhymes and no near rhymes, and images introduced in one couplet never return. A line about "sinkin' ships" appears once and is abandoned. A chorus couplet — "Bankrolls on the table / Watchin' local cable / Hatin' that I'm able" — never specifies what the narrator is able to do or why he resents the ability.
The delivery has its own problems. Harding pointed to a "complete lack of flow" and noted that the title line is sung with the syllabic emphasis in the wrong places, forcing an unnatural syncopation that no working rapper would choose.
“No half-competent rapper would ever sing the title line 'I just let the rubber band snap' in such an awkward manner. The syncopation is highly unusual, emphasizing all the wrong syllables.”— Charlie Harding, Songwriter and co-host of Switched on Pop
Live appearances have made things worse rather than better. Early in-studio performances featured Fenix lip-syncing, and later ones kept his live vocals buried under the studio recording. Brief moments where the backing track drops out — intended to prove authenticity — instead expose that he cannot hit the recorded vocal range or hold the accent. Fenix has argued the gap is a matter of AutoTune and vocal processing.
That defense does not survive contact with the technology. Producer Curtiss King compared AutoTune to spellcheck: designed to nudge pitch, not to invent range or accent. Music critic Anthony Fantano made the same point directly, noting that AutoTune would not extend a performer's vocal range or introduce an accent. Both critiques are structural, not aesthetic.
If the song is AI-generated, it was made with a weak model. Harding said he would assume the track was written by someone who had never touched a keyboard, and warned that more sophisticated music models have already fixed the artifacts and awkward rhythms audible in "Rubberz." The implication is that the ceiling for chart-viable AI music is rising fast, and the audible tells that make this case debatable will not be audible for long.
“I am concerned that audiences find this song interesting when it is created by one of the lesser generative AI music companies with a terrible model. More sophisticated models have already made big improvements in the audible artifacts and awkwardly sung rhythms.”— Charlie Harding, Songwriter and co-host of Switched on Pop
Fenix has posted clips he says are Pro Tools sessions, which prove nothing on their own — a session file can hold any audio a producer imports. Without the original stems, isolated vocal takes, and dated project files, the accusations will follow the track for as long as it charts. The major labels have been circulating proposed rules to keep AI-generated tracks off the charts, and Suno lost a copyright suit in Germany at the end of July, so the industry pressure to draw a line is already building.
The commercial fact is the one worth sitting with. A song that multiple credentialed listeners believe was generated by a mediocre AI music model reached the top 60 of the Hot 100 while the argument was still being had in public. That is the story for the AI music market: distribution and streaming economics no longer require the model to be good, only good enough to pass on first listen. Every incremental improvement in Suno-class systems from here shortens the window in which anyone — labels, detectors, or fans — can tell the difference at all.
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