|About half the size of a grain of rice.|
These were taken from the inside, through double panes, while it poured rain outside. The window is relatively sheltered, so the white capsules were just damp.
I went outside to check, and they looked the same from that side. But I was getting wet, so I took no photos.
There were several clumps, all with those little cyan spots in them. They have the texture, to look at, of bird poop. Formed pellets of bird poop.
What do you think? Insect eggs? Bleached snail poop? The beginnings of a stealthy invasion of interstellar pod creatures?
#UPDATE: I went out and brought a clump in. It detached itself from the glass with only a touch. (That goes against insect eggs, which would be glued down.)
In spite of the heavy rain, they felt barely damp. They crumbled easily.
I looked at them under the microscope. The little cyan specks are still there, and the white mass has a bit of sparkle, like sugar crystals.
Crumbled, they are the same all the way through. The crumbs look fluffy, sort of like my sugar substitute, the kind you spoon into your coffee, not the packet stuff.
There is no odour that I could detect.
I vote for snail poop, bleached. I've never seen white snail poop before. I wonder what they've been eating.