A 21-year-old social media influencer went missing last month while hiking the second highest peak in the US — and he likely slid to his death attempting a dangerous “shortcut” without crucial safety gear, the last person to see him has revealed.

Joseph Brambila, an experienced trekker who documented adrenaline-filled adventures for a growing audience on YouTube, disappeared during a solo birthday climb of Mt. Whitney in California.

He is believed to have met a terrifying end after trying to cut time off his descent by “glissading”– sliding down the steep, snowy slopes on his buttocks, according to fellow hiker Luis Buenrostro, who spoke recently with the Los Angeles Times.

Buenrostro, believed to be the last person to speak with the young adventurer, told the Times that Brambila made the fateful decision to slide down the mountain’s icy face without critical equipment: a helmet and ice axe.

“He said he was gonna be good, so I thought, he’s gonna be good,” Buenrostro told the outlet of their final exchange.

Glissading is a common but high-risk technique used by mountaineers to descend rapidly that can be safe if done in the right spot.

According to a post from the American Alpine Institute, “the desire to glissade though should be tempered by the reality…and the reality is that a lot of people get hurt glissading.”

To make the move even riskier, Buenrostro claimed that Brambila lacked the tools essential to lessen the danger. Without an ice axe, a sliding hiker has almost no way to slow down if they pick up lethal speed.

The tragic theory aligns with grim reports from search teams. Other hikers later reported to the Inyo County Sheriff’s Office that they spotted a motionless body about 1,000 feet below the cables on the wide slope coming downfrom Trail Crest — which is where the two hikers last interacted.

To date, no human remains have been discovered or recovered. Ferocious winter conditions, including deep snow and unstable ice, have forced the sheriff’s office to suspend the search until spring.

According to the Fowler-O’Sullivan Foundation, an organization that is providing assistance to Brambila’s family, he set out to climb the 14,505 feet summit on Nov. 10 and was scheduled to return on Nov. 13.

While his family described him as a prepared hiker who enjoyed solitude, the mountain’s winter conditions appear to have overwhelmed even his previous experience on the peak.

For now, the mystery of his final moments hangs over the frozen landscape, leaving friends and family to wonder if a quick way down cost the youngster his future.