It may not be part of the same canon or continuity as the animated series. Adventure Time: Marceline and The Scream Queens Issue 2 is a part of the Adventure Time comic miniseries. It was published by BOOM! Studios.
Traveling Wilburys. The Traveling Wilburys (sometimes shortened to the Wilburys) were a British-American supergroup consisting of Bob Dylan, George Harrison, Jeff Lynne, Roy Orbison, and Tom Petty. The band recorded two albums, the first in 1988 and the second in 1990, though Orbison died before the second was recorded.
Listen to the song here. The Foggy Mountain Boys was an American bluegrass band. The band was founded by guitarist Lester Flatt and banjo player Earl Scruggs. The group is considered one of the premier bluegrass groups in the history of the genre.