A baseball is in my air duct

My heating and air conditioning system has been making a very odd noise as of lately. I am not exactly sure what on earth is going on with it. Every time the heating and air conditioning system goes on, I hear this really loud rattle type sound. Also, it kind of sounds like something is rolling around in the air ducts. There is no way I can crawl up into the ductwork to see for myself, so I let it go for a while. The other day, I noticed I was not getting any air coming out of the air vents. So I called my friend over who knew a thing or two about heating and cooling systems. He went up into the air ducts and found that there was a small baseball stuck in there! How a baseball got into my ductwork and air ducts is unknown. But, my friend got it out of there, and my heating and air conditioning system was flowing properly once again. The baseball was possibly in there from before I moved in. There could have been kids playing, and then the baseball went into the air ducts somehow. Possibly from the outside. The entire concept is confusing to say the least. I live alone and do not have any kids, so I know I did not get the baseball stuck in the ductwork and air ducts! Hopefully, this is the end of anymore unusual situations in my home or my heating and air conditioning system! But who knows, they always say to expect the unexpected. This for sure falls in that category!