Halloween was a bummer

I always anticipate Halloween. The strange oval and circulor transparent artifacts that have shown up on some of my Halloween pictures are sure to keep one guessing. But this year, using the same cameras, films, etc; not one strange artifact appeared. Once I got a few of these strange disks on a couple pictures that I had taken just prior to Christmas,  I will undoubedly take pictures over Thanksgiving and Christmas and I will ever be alert fot the disks but our best season has passed with no luck. Any hunters of the strange, out there, who have any helpful ideas? I'm open to suggestion.