Same behavior in my cat as in the first one you describe. Did it for a year or two, not my idea, the cat is the one that thought it up. No treats or training in

Same behavior in my cat as in the first one you describe. Did it for a year or two, not my idea, the cat is the one that thought it up. No treats or training involved, the cat would bring me the ball to throw and then go get it. Doesn't do anything like that now, sleeps most of the day, 17 years old now. Still gets the zoomies once in a while but not like back then, same as me.