It's an army of, wait for it, red and yellow..
Red 'n' yellow army, Red 'n' yellow army, Red 'n' yellow army, Red 'n' yellow army... (repeated...)
PTFC on SpotifyRed and Yellow Are the Colours We Love Chant
Thanks to Michael Green for the lyrics
We've Followed the Thistle for Many a Day Chant
Great Partick Thistle song