randi reynolds answered 9/5/2009 I Found A Spider In My Basement In Michigan It Was Black And Had White Spots On It Back, What Is It And Is It Harmful To Pets And Children? I have found a spider in my yard that is black and it has white spots...but it has 6 horns on it. It shows no type of defence and it had a very large sack on it. And it makes the weirdest web ever!