In Catalonia, families include a unique log with a playful face named 'Tió de Nadal' at Christmas. What's special about the log?

It provides small gifts when struck with sticks

Who was the grandfather of King David? In the game series "Mass Effect", what is the name of the alien species Garrus Vakarian belongs to? What is the Spanish term for a Nativity scene? The term 'Iron Curtain' was popularized by which historical figure? What is the Polish name for Easter cakes often baked in a lamb-shaped mold?