Wow. You'd think so, but, nope. Still, maybe it is spider egg cases of some kind.
Why do I not have an entomologist buddy? (That's the term, right? for people who study bugs?) I could just call up and say "Hey, Maxine, come look at this thing and tell me what the heck you think it is!"
What's really cool about all this, or one thing really cool, is that on another forum I frequent (which has nothing to do with gardening) there's a young guy in the UK who is very intrigued by all this and is asking very protective questions about whether Killer is going to be safe outside, and hopes this white thing I found doesn't have something in it that will be dangerous for Killer, etc. It's quite endearing!
:)