There’s something fitting about Chief Keef and Lex Luger collaborating in 2017. Luger, one of the architects of modern trap production, broke out with eight Top 20 rap hits in 12 months (beginning May 2010) and has had only one since (Wiz Khalifa and Travis Scott’s “Bake Sale”). Today, Luger has more or less been forgotten by the rap industry at large, washed away amid a sea of imitators and surrogates. His sound was explosive and opulent, and it was wholly singular—until it suddenly wasn’t, first becoming recyclable, and then disposable.

Keef, meanwhile, should be considered nothing short of a prodigy. In 2012, at 17, he released the drill opus Finally Rich, and in the years since he’s continued to grow bolder and more daring, experimenting without concern for who likes what and distancing himself further and further from the sounds that made him so popular in the first place, losing two deals in the process. Keef’s refusal to produce a proper sequel to what may forever be hailed as his masterwork has caused interest in him to wane. Chief Keef is now just 21 years old, at least a year younger than current it-rappers Lil Uzi Vert and 21 Savage—contemporaries Keef inspired when he was still in high school, who have already been tapped to succeed him. Both Keef and Luger are hugely influential, with elements of their sounds and aesthetics still impacting radio today, yet demand is down for both, just for different reasons. Rap is one of few genres where artists can be deemed obsolete before turning 23. It churns out new models fast.

But with someone as mercurial and talented as Keef, moments of brilliance can materialize in an instant. They’re likely to happen when no one is looking. This is the case on his latest mixtape, Two Zero One Seven, where Keef proves he can produce more dynamic songs than any of his progeny while sleepwalking. And instead of attempting to reclaim lost territory, he dares to venture even deeper into open space.

The 17-song tape is weird and expansive, and it reintroduces many of Keef’s most compelling quirks. On some songs, he’s almost deadpan; on others, he’s excitable. His sing-songs can scan as theatrical: near the start of “Fix That,” he warps his vocals into something resembling a cartoon voiceover, but by the end he’s unleashing a creaky falsetto. “Running Late” presents a rousing rendition of the creepy lullaby from Nightmare on Elm Street. Sometimes he mumbles, sometimes he chants. He often uses his voice as another instrument in his productions—it can be percussive or melodic or even amelodic in service of structure or flow.

No matter how they’re delivered or what their purposes, his raps are packed with refreshingly bizarre non sequiturs and stream-of-consciousness one-liners. His flows sputter, stagger, or just flat out drill. He’s a much better writer than his heirs, dropping gems like “My watch tried to take your bitch from me” (“Empty”), “Bitch, I’m still with the street shit/Clip longer than a selfie stick” (“Falling on the Floor”), and “the diamonds in my ear giving me a brain freeze” (“Trying Not to Swear”). He seems uninterested in honing the skills he already has, opting instead to try and figure out new ones. With every passing song, he moves onward.

Luger produces a handful of tracks on Two Zero One Seven, and the best, “Control,” is like the audio version of a miniature Tron light cycle race. But it’s Keef himself who produces the majority of the project, and it’s this aspect of his creative repertoire that’s grown the most. Earlier beats were unhinged, but these do more than just move in unorthodox ways; they pop and glow. Keef seems to have little use for traditional “bangers” and he’s no audiophile (the quality of his sounds can vary dramatically), but he is willing to try just about anything and he has remarkable instincts. He isn’t afraid to induce sensory overload with busy arrangements, but he’ll also strip sounds bare and leave them exposed.

One minute he’s tinkering with piano chords, the next he’s making minimalist 8-bit trap, the next he’s channelling late ’00s Shawty Redd. He’s impossible to predict. On “Trying Not to Swear,” the beat bottoms out and the sample gets muffled and distant, lined by the sound residue from the hum of a vibrating 808 kick. “Knock It Off” and “Dope Smokes” utilize keyboards with different intentions—the former as a pulse, the latter as an accent—and both have bite, cacophonous but never discordant. These songs on Two Zero One Seven are microcosms of the artist who made them. They can be difficult to read and sometimes even harder to understand on a functional level, but they’re quite exhilarating.