Bon Iver frontman Justin Vernon joined his longtime associates —and former bandmates—Megafaun at Brooklyn, NY’s Baby’s All Right on Friday night. Vernon played with the psychedelic-leaning folk-rock group throughout their entire set, alternating between guitar and bass at different points throughout the night. Though a variety of guests were rumored to sit in with the group, Vernon was the night’s only surprise performer.

Vernon also performed with Megafaun throughout their shows at Durham, NC’s The Pinhook on April 29 and 30 as well as Washington, DC’s DC9 on May 1. During Wednesday night’s show, The Mountain Goats’ John Darnielle joined Megafaun and Vernon for a cover of the Grateful Dead’s “Friend of the Devil,” while Hiss Golden Messenger’s Mike Taylor took the stage for Megafaun’s “Real Slow” and his own “Mahogany Dread.” The Tender Fruit’s Christy Smith also sat in on “The Longest Day” and Vernon moved to the front of the stage to sing on Johnny Cash’s “Unchained.” (Before launching into “Friend of the Devil,” Megafaun’s Brad Cook described the song as by a band “that changed all of our lives.”) On Thursday, Matthew E. White emerged during Megafaun’s DC9 performance for “His Robe,” “Real Slow” and “Kaufman’s Ballad” at the end of the night.

Vernon has a long history with the members of Megafaun dating back to their high school band Mount Vernon. After that project, Vernon played with all three members of Megafaun in the roots-rock group DeYarmond Edison. More recently, he has toured the trio as part of the R&B-oriented side-project Gayngs and with Megafaun’s Phil Cook in The Shouting Matches. He will slated to record with the group as part of The National’s forthcoming Grateful Dead tribute.

Friday’s Megafaun performance was the band’s last for the foreseeable future. Brad Cook will spend the next few months touring with Ween’s Aaron Freeman as part of his new solo project.