Shock G, the bombastic rapper who fronted late ’80s/early ’90s hip-hop collective Digital Underground, has died, according to an Instagram post Thursday (April 22) from his onetime groupmate Chopmaster J. He was 57.

The artist’s passing was confirmed in a statement from his family. “Our son, brother and friend, Gregory Jacobs, also known as Shock G, suddenly passed away today,” the statement reads. “The cause of death is currently unknown. We truly, truly appreciate all the out-pouring of love and concern. Please keep us in your prayers at this very difficult time.”

Digital Underground was best known for their 1990 hit “The Humpty Dance,” and Shock G (real name: Greg Jacobs) was front and center for the song’s MTV-favorite video as his alter ego Humpty Hump.

“34 years ago almost to the day we had a wild idea we can be a hip hop band and take on the world,” Chopmaster J wrote on Instagram. “Through it all the dream became a reality and the reality became a nightmare for some. And now he’s awaken from the fame long live shock G Aka Humpty Hump and Rest In Peace my Brotha Greg Jacobs!!!”

Digital Underground was formed in Oakland, Calif., in 1987 by Shock G, Chopmaster J and Kenny-K, and the collective included a revolving door of more than three dozen members over its almost three decades of activity — including some of the earliest recordings from a young Tupac Shakur.

The group had four top 40-charting hits on the Hot R&B/Hip-Hop Songs chart, including the top 10 smash “The Humpty Dance,” which also spent five weeks at No. 1 on the Hot Rap Songs chart in 1990 and peaked at No. 11 on the all-genre Billboard Hot 100. The song also garnered a Grammy nomination for best rap performance by a duo or group. “The Humpty Dance” was one of two top 20-charting hits on the Dance Club Songs chart, alongside 1991’s “Same Song.” The latter track housed an early appearance of 2Pac on a commercial recording, as he raps the final verse on the track. He’s introduced in the previous verse by Shock G, who raps “2Pac, go ahead and rock this.”

The group also placed six entries on the Top R&B/Hip-Hop Albums chart, including a pair of top 10s: 1990s Sex Packets and 1991’s This Is an E.P. Release.