Fun story:

When Pope Paul III heard that Michelangelo had finished the top part of the wall and was removing scaffolding, he came immediately to see the progress. His reaction was to fall to his knees and pray. The Pope's Master of Ceremonies, Biagio da Cesena, had also come to view The Last Judgement, and his reaction was to call it disgraceful! Da Cesena thought the multitude of nudes were sacrilegious, and he predicted that the wall would someday be destroyed.

Pope Paul III was astonished and angry, and he said that he'd excommunicate anyone who touched the wall.

Almost immediately, Michelangelo had an assistant stucco the lower right corner of the wall, and he painted da Cesena as Minos, the judge of Hades. Word got back to da Cesena and he demanded another visit, with the Pope in tow. Here, I quote from Irving Stone:

"You see, Holy Father," cried the Master of Ceremonies, "the report was true. Buonarroti has painted me into the fresco. With some kind of repulsive serpent for my genitalia."

"It's a covering," replied Michelangelo. "I knew you would not want to be portrayed wholly naked."