Song by the Beatles: Mean Mr. __
Puzzle 12 of Running a Marathon Pack
Question is: Song by the Beatles: Mean Mr. __
and the answer is: MUSTARD
Word Meaning:
MUSTARD — A plant of certain species of the genus Brassica, or of related genera (especially Sinapis alba, in the family Brassicaceae, with yellow flowers, and linear seed pods).
Definitions from Wiktionary.