Think about the calf's death is a popular expression used when someone seems to be distracted, introspective, aloof from everything and very thoughtful.
It is considered a popular saying quite common in Brazil and Portugal. However, there are some disagreements between the stories that supposedly gave rise to this expression.
The most accepted theory speaks of a story from ancient Hebrew traditions, where the Hebrews had the custom of offering calves to God, as a sign of gratitude or redemption for their sins.
According to legend, King Absalom's youngest son was very fond of a small calf that his father had and did not want it to be sacrificed. But Absalom did not spare the animal, sacrificing it in honor of God.
It is said that the boy, since then, has spent the rest of his life thinking about the death of the little calf, acting in a sad and distant way from everyone. Some versions of the legend say that the boy would have died a few months after the calf's death, due to the gravity of his grief.
Another supposed story about how this expression would have originated is typical of Portugal. According to legend, there was a man named Bezerra who would have committed several heinous crimes in the city of Porto. Residents, outraged by the criminal's actions, violently beat him for several kilometers.
Bezerra's death would have been so violent, that ever since, when someone was seen with a pensive or distant air, it was said that he was "thinking about Bezerra's death".