Dumpstaphunk brought their brand of dirty New Orleans funk to Sweetwater Music Hall in Mill Valley, CA last night for a very special Halloween show.

It wasn’t just special because of the holiday, either. As noted by Live for Live Music, the Ivan Neville-led group also got some help from Grateful Dead guitarist (and co-owner of Sweetwater Music Hall) Bob Weir, who joined them on stage for a rendition of Earl King’s classic “Big Chief” and The Dead’s own dance-funk staple, “Shakedown Street.”

Weir has been a busy man lately. The rock icon has been touring with the popular Grateful Dead spin-off Dead & Co (which features John Mayer) for over a year now. He also recently wrapped up a tour in support of Blue Mountain, his first album of new solo material in over 30 years.

Watch his Dumpstaphunk’s collaboration with Weir here: