I have an invisible Friends List

I don't really know what happened. I was taking a few friends off my News Feed because they just post too much. Then I went to my Friends page, and suddenly almost everyone is on an extra list, that I did not create! To confuse matters further, this list appears not to have a name. Below many friends' names I see a comma followed by the list on which they are included. On the right side is a drop-down menu that reads "2 lists" where previously it read "1 list." On the drop-down menu, only one list is checked.

I'm very confused. Any help that anyone can provide will be greatly appreciated.