White-egg birds nest fungus

I have NO idea what this is, not even sure if it belongs in the arthropod category or not. I found about 10 of these TINY, round, nest-like shells growing/attached to the dead stems of White Loose Strife (5th picture is of the White Loose Strife patch that's gone to seed where I found these things). Each of the "shells" had about 3 small, creamy-white eggs or seeds sticking inside of them.
Ball point pen is for size reference.