The box is the fourth ornament
This is pretty weird, to say the least. If there were like 100 ornaments, nobody would miss one or two missing pieces. However, if the box says there are four while only three pieces belong to the set, well, you’re just causing confusing the public. And if there’s one thing nobody needs during Christmas time, it’s mass hysteria.

Since when was missing 25% of the box’s contents okay? Also, can’t the company get sued for false advertising? If so, we call dibs on making a million bucks by bringing this company to court! Maybe the box is the fourth ornament that you can give your cat.