Bob Weir, a founding member, guitarist, and singer of the iconic rock band the Grateful Dead, has died at the age of 78. Weir, known for co-writing classics like "Sugar Magnolia" and "Truckin'," was a central figure in the band's sound and enduring legacy. He passed away after a battle with cancer and underlying lung issues, as announced on his Instagram. Weir remained a prominent face of the Grateful Dead's music through various projects after Jerry Garcia's death in 1995.