He is widely known for his negative reaction to the nude figures presented in Michelangelo's fresco of The Last Judgment in the Sistine Chapel.

He would also act in this role to Popes Adrian VI, Clement VII, and Paul III.

[1] In a story well known from the 16th century onwards, in a number of slightly different versions, Biagio is said to have complained about The Last Judgment, saying "it was disgraceful that in so sacred a place there should have been depicted all those nude figures, exposing themselves so shamefully".

In response, Michelangelo worked Biagio's face into the scene as Minos, judge of the underworld (in the far bottom-right corner of the fresco) with donkey ears (indicating foolishness), while his nudity is covered by a coiled snake biting his penis.

It was widely said that when Biagio complained to Pope Paul III, the pontiff joked that his jurisdiction did not extend to hell and the portrait would have to remain.