What a great find and a fabulous macro picture. It probably have been blown of your oak tree. To me it looks more like a lichen, possibly "Usnea trichodea" or how you maybe call it, part of an old mans beard. There are warblers who make there nest from this lichen,... and herbalist use it to treat infections, as it is like a natural antibiotic,... and, and, and. Such an intersting stuff. You are right, it's weird and alienlike,... so I like it! Fav of course.
