In 2012, following a stint in a Florida punk band and an apprenticeship under R&B polymath Ne-Yo in Atlanta, Matthew Musto joined the singer/songwriter Mike Posner for a co-write in Los Angeles. "Our first real session, we wrote Bieber['s 'Boyfriend']," Musto remembers. That song subsequently went to No. 2 on the Hot 100 and sold over three million copies.

"It made me think I'm never gonna miss," says Musto, who now records as blackbear. "I went crazy. I was poor my whole life. When I was a millionaire at age 21, what would you do? As soon as I got rich, it was mimosas every morning. I was taking my friends to Six Flags every weekend; we were flying to Hawaii; we did whatever we wanted."

At least, until last year, when the hard living caught up with Musto. What he thought was a nasty bout of acid reflux turned out to be a life-threatening case of pancreatitis brought on in part by substance abuse. "One in three people would have died from the severity of my attack," Musto says. "I had a large surgery where they cut me wide open."

While recovering in the hospital, Musto started to come up with many of the songs for the new blackbear full-length, Digital Druglord, released last month. Lead single "do re mi" charged onto the Hot 100 last week at No. 87, the first blackbear track to ever crack that chart, and Digital Druglord debuted at No. 14 on the Billboard 200. "It's a good time in the Beartrap world," says Musto, who no longer drinks. "I'm waiting right now for the president of a label to see if he wants to buy my label for millions."

It's fitting, then, that Musto is talking on the phone poolside. "I'm in some suede jumpsuit shorts, a cut-off Raf Simons tee, a pink Supreme hat," he says. "I'm really livin' my fullest potential life."

A little over a decade ago, Musto dropped out of high school when his punk band was signed; he was just 16 at the time. Soon he ditched the group and started putting songs he describes as "electronic folk" on MySpace. He was discovered there by a manager named Tabari Francis, who still helps Musto today.

"Tabari sent my demos out to anybody and everybody," the singer recalls. "The ones we got bites back from were Ultra Records, who probably wanted me to be the next Matthew Koma [a writer who frequently works with electronic music producers] before Matt Koma even happened, and Akon, [but] I don't know where I would fit in that camp. So we decided let's go check out Ne-Yo.

"I was such a huge Ne-Yo fan," Musto adds. "I respect anybody that is very in tune with their feelings."

The time he spent in Atlanta served as a crash course in the music business. "That's where I learned: whoa, I can sell these songs that I don't want to necessarily sing for me," Musto says. He wrote daily and put some of the demos out for free on PureVolume, an early MP3 site. Some recordings also found their way to Mike Caren, a longtime A&R who is now the CEO of Artist Partners Group and a Creative Officer at Warner Music Group. Caren flew Musto to L.A. and put him together with the producer MdL, who would also work on Bieber's "Boyfriend."

Following the success of "Boyfriend," Musto became a big spender, and pivoted almost immediately to start recording himself. (He still writes for other artists occasionally, but only on projects he wants to work on, like the new Linkin Park album.) The second blackbear project, Deadroses, included a listless, love-drunk tune called "Idfc," which stands for "I don't fucking care." The track came out on Valentine's Day in 2015 and bubbled quietly on the internet; roughly 18 months later, it cracked Billboard's Hot R&B songs chart. "If it didn't have the F word in the chorus, I'm pretty sure it would've played all over the radio," Musto says. "I have an independent plaque, and I'm so proud of it. That's my baby."

blackbear uses polished rap beats as a backdrop for fuzzy, half-remembered tales of sozzled nights and white-hot eruptions of emotion, often directed towards unnamed romantic partners. Though the feelings come fast, Musto sings in an unemotional tone, and the instrumentals rarely alter or shift dynamics, so there's a strange disjunction between medium and message. His songs induce whiplash as they swing between overwhelming feelings of attachment — "Tell me that you love me/ Even if it's fake" — and vindictive kiss-offs: the refrain of his latest single is, "I'm so fucking done with you."

When asked if any female fans might be put off by the direct broadsides on songs like "do re mi," Musto says, by way of explanation, "It's kind of like watching Mean Girls. A lot of drama in L.A., a lot of talking, a lot of telephone. That's Hollywood." And in a sign that Musto's fans perhaps prefer the hot-blooded, accusatory stuff to the blasé numbers, "do re mi" debuted higher than "Idfc" even peaked. The more drama, it seems, the better.

Though he has plenty of label connections — when he released a collaborative album with Mike Posner as Mansionz earlier this year, the pair obtained a deal with Island almost immediately — Musto continues to pursue the independent route. Part of this is practical. "I'm gonna be completely honest: my annual income is more than what a label could offer me at the moment," he says. But this is the way he wants it, too: "I like to be in charge of how everything happens."