Two from the same band. Spirit was an odd group - their drummer Ed Cassidy had fought in WWII, then drummed on the West Coast with a number of top tier jazz names for some years before moving into rock music, and was 42 when the direct predecessor group was started in 1965. His stepson Randy California was only 14 at the time, and during an early hiatus spent several months playing in Jimi Hendrix's band before Jimi went to England and made a major name for himself.
From the first (self-titled) 1967 album (which contained the track "Taurus" that was the center of a long-running plagiarism lawsuit against Led Zeppelin's "Stairway to Heaven"), the song "Uncle Jack", a very period psych-rock piece.
A bit over three years (and three albums) later, from
Twelve Dreams of Dr. Sardonicus, a song nominally about Cassidy (with the title referencing his shaved head), "Mr. Skin". The change is radical - the band's sound is tighter, and the recording techniques have advanced considerably - and does a good job demonstrating the maturation in both Spirit specifically and the overall heavier rock scene in the intervening period.