What did Elya Yeltnats forget to do before he left on a ship for America In the book Holes?

Before leaving for America, Elya Yeltnats forgot to bring a pig named Miss Katherine as a gift for the woman he loved, which was crucial for fulfilling a promise to her family. This oversight ultimately led to a series of unfortunate events that affected his life and the lives of his descendants. His failure to remember the pig is a key part of the backstory that connects to the main plot of "Holes."