A$AP Mob founder A$AP Yams has died at age 26. The cause of death is currently unknown.

Yams ran a popular hip hop blog before founding A$AP Mob, a collective that now includes rappers like A$AP Ferg and A$AP Rocky. “Yams is the hip-hop encyclopedia,” Rocky told New York Times for a 2013 profile on Yams. “He’s no joke. That’s one person I can’t front on when it comes to music.”

A$AP Mob members have been posting tributes to Yams online since news of his death broke, including one from Ferg that addresses Yams directly: “You were the brilliant mind, you put us on Game, you changed our lives,” he said in a Tumblr post. “You changed my life, you changed the world.”

Other big names in hip hop like Russell Simmons and Drake have also posted condolences, and fans are remembering Yams by retweeting some of his funnier tweets under the #YamsTweets hashtag.

RCA Records, which represents some of the A$AP Mob artists, also offered their sympathies in a statement. “All of us at RCA Records are shocked and saddened to hear of the death of A$AP Yams. As one of the creative forces behind A$AP Worldwide, Yams’ vision, humor, and dedication to the members of A$AP Mob will always be remembered. We extend our heartfelt condolences to his family and friends.”