We at Stereogum stopped running our Mixtape Of The Week column earlier this year; it first became The Week In Rap and then Status Ain’t Hood when some other website claimed to own the phrase “The Week In Rap.” But in the back of my mind, I knew we’d face a situation like this: One week when a rap mixtape completely obliterates all the commercially-available albums that come out during a given week. This week has its share of good albums. I like the new Gangrene and the new Palehound, and at different points, I planned on writing both of them up in this space. But this new Free mixtape is so far beyond any proper album this week, even though it’s very much not a proper album. In fact, it’s barely a mixtape, in the way that term has come to be understood. Mixtapes today are basically just street albums: All-original full-lengths, full of complete songs, that would’ve probably come out on indie labels during a healthier music-business era. This, on the other hand, is two guys spending a day in a room together, bullshitting whatever comes off the top of their heads. The whole thing lasts six tracks, and it seems like not one single word of what either rappers says was written or planned-out beforehand. It’s two strange, talented people saying whatever pops into their heads and figuring things out from there. It should, by rights, be terrible. But it’s so full of joy and warmth and genuine good feeling that it stands as one of the most purely pleasurable things I’ve heard all year.

Here’s the story, as we understand it: A couple of weeks ago in Chicago, Chance The Rapper and Lil B spent the day together making an album. That’s it. That’s pretty much all we know. The two were in town that weekend, for different reasons. Chance was headlining the Pitchfork Music Festival, playing a set so clearly rehearsed and planned-out that it’s a wonder he had the time to knock this thing out in between practice sessions. Lil B was in town to do a Boiler Room show. Maybe everything lined up just right, or maybe Lil B just took the Boiler Room booking because he’d been planning to make this tape with Chance for months. Maybe they just texted each other the day before and realized they had the afternoon free. The beats are all original, though we don’t know who produced them because the tape doesn’t come with production credits. (At one point, Lil B shouts out the Seattle producer Keyboard Kid, who’s collaborated with him before, so maybe that’s who made the music. Or maybe Lil B was just saying hi.) On opening track “Last Dance,” Noname Gypsy, the sole guest on the tape, pauses for a second: “Uhhhhh, I’m not a good freestyler. I don’t know what to say.” (She’s still a thousand times better than you or I would be in that situation.) Then, later on: “This is gonna be a whole freestyle mixtape? That’s crazy!” It’s like she just learned about it minutes before. And yes, it is crazy.

It’s nothing new for Lil B, of course; he’s not the type to sit and think about his verses beforehand. The Based God first made his name as one fourth of the teenage Bay Area group the Pack, quietly influential rap minimalists who had exactly one national hit in the sneaker anthem “Vans.” A few years after that, though, Lil B started throwing head-blown half-spoken-word freestyles on a series of MySpace pages and unlocked a whole new persona: A giddy, dippy positive-lifestyle motivational-speaker type whose music only had a glancing familiarity with traditional rap. He was immediately a joke to a whole lot of people on the internet, and these days, he’s known more as a human meme generator (most recently, for his eerie ability to curse NBA All-Stars) than as a rapper. As someone who’s suffered through a couple of his live shows, I can say that some of this reputation is justified. But Lil B’s whole freewheeling, unanchored, love-the-world improv style makes him important for reasons that go way beyond any “thank you Based God” Photoshop jobs you might’ve seen. Younger rappers like Chance looked at Lil B and saw someone completely willing to subvert or ignore rap’s rigid rules, to follow his own bugshit muse wherever it might lead him. That freeform expansiveness means that plenty of his mixtapes are indulgent slogs. But collaborators bring out the best in him. In its in-the-room excitement, Free actually reminds me of Pretty Boy Millionaires, the 2010 mixtape that Lil B made with Soulja Boy. Chance and Soulja are obviously nothing alike, but they both seem to inspire a certain energy in Lil B that manifests as rigor. On that tape and this one, Lil B is actually rapping, not just rambling about life’s journey through space or whatever.

For Chance, this tape comes in the midst of big career changes (he’s a bona fide festival headliner now) and even bigger life changes (he’s about to become a dad). It’s his follow-up to the Donnie Trumpet & The Social Experiment album Surf, one of the year’s best albums and, in a lot of ways, the opposite of Free. Surf was a big production, full of big-name guests and lush instrumentation. It’s a product of studio perfectionism, and it had a beautifully defined arc to it. And considering that Chance learned his art in Chicago’s after-school freestyle clubs and how-to-make-rap public-library activity groups, Free is more a return to Chance’s roots than another Acid Rap-style tape would be. He’s a sharp, detailed writer, and we don’t get to hear that side of him on an improvisation exercise like this. But Chance’s excitable style, heavy on yips and yammers, is perfect for this sort of thing. He’s a quick thinker, and the mere activity of rapping off the top of his head pushes his voice into some interesting places. He mentions Jordan constantly, both Michael and the river. (“Yeah, I’m back rapping about Jordan / Because the shit’s so important,” he giggles at one point.) He second-guesses himself: “Grocery shopping for my mama and daughter / I’m feeling like I shouldn’t involve them / But now I move too quickly.” He talks about the expectations that people put on him: “I had to dissolve ‘em like acid to bases / They want me to go back to Acid, they’re basic / Shit, that’s just tasteless.” He yells at the engineer to keep the beat going when it should logically end. He’s just on fire throughout.

More than anything, Chance and Lil B sound overjoyed to be in a room together. They keep shouting each other out. Lil B also shouts out a host of other rappers and musicians — Lil Wayne, Kendrick Lamar, Jay Electronica — who could conceivably benefit from making a tape like this. Whenever one of them runs out of things to say, the next one is there to catch him and pick it up. Sometimes, they’ll pause between verses and just talk, and that talking will slowly give way to rapping. And then there’s “Amen,” the absolutely lovely nine-minute track that features barely any rapping and a whole lot of singing, the two of them piecing together melodies over subdued finger-snaps and a contemplative organ hum. The first time I heard it, it didn’t even occur to me that the song was going on forever until after it was over. I was caught up in the headspace, just like the two of them were, and it swept me away. And if you approach Free with the right state of mind, it might do the same to you.

You can download Free (Based Freestyles Mixtape) for free at DatPiff. Stream it below.

Other albums of note out this week:
• Gangrene’s hard, psychedelic, fun-as-hell indie-rap party You Disgust Me.
• Palehoud’s smart, incisive, melodically sharp DIY punker Dry Food.
• The Good Life’s heavy-hearted Midwestern indie return Everybody’s Coming Down.
• Cate Le Bon/White Fence duo Drinks’ psych-pop debut Hermits On Holiday.
• Rayland Baxter’s breezy, eclectic Americana record Imaginary Man.
• Slime’s gnarly debut Company.
• Soft Fangs’ intimate DIY document Golden.
• Blackalicious’ long-awaited conscious-rap comeback Imani, Vol. 1.
• Media Jeweler’s antsy guitar-charged $99 R/T Hawaii.
• Slow And Steady’s emo-revival debut In Time We Belong.
• Doubting Thomas Cruise Control’s conceptual indie LP Remember Me John Lydon Forever.
• Bleak’s metalcore churn We Deserve Our Failures.
• Janelle Monáe’s crew compilation Wondaland Presents: The Eephus EP.
• Morley’s In Defense Of My Muse EP.