There were two identical pet birds. One was named Sorrow, the other Sorrow Eater. When the owner woke up the next morning, there was only one bird in the cage. The owner knew exactly what had happened, even though he was asleep when it happened. How could he know?
He planned for it to happen. When he named his birds, he knew that the Sorrow Eater would eat Sorrow, because it was a SORROW EATER.