“I guess it’s because the big toe sticks up.”
— Terry Gilliam, explaining his choice for Monty Python’s animated Obliterating Foot.

Animation frame from the opening titles to Monty Python’s Flying Circus

The foot originally belonged to Cupid in Venus, Cupid, Folly and Time, a painting from the 1500s by Agnolo Bronzino.

Detail from Agnolo Bronzino’s Venus, Cupid, Folly and Time

Source: Jones, Jerene (1981, December 21). The Only Yank in Monty Python Stares Down Critics as His Time Bandits Steals $24 Million. People magazine, Vol. 16, No. 25.