On August 6, 2010, when Umphrey’s McGee performed the mash-up of "Immigrant Song" and "Thunder Kiss '65" at Penn's Peak, they were riding the wave of their album "Mantis," which was released in 2009. This album marked a significant evolution in their sound and was noted for its more progressive and complex compositions compared to earlier works. At this point in their career, the band was actively touring and leveraging their reputation for intricate live performances, showcasing their ability to blend genres and engage audiences with seamless medleys. The choice of covering such iconic songs in their setlist reflects their penchant for eclecticism and their commitment to honoring rock influences while crafting their unique sound. This performance also highlighted their status as a prominent live act within the jam band scene, known for spontaneity and improvisation.