An array of tiny eggs appeared on the outside of our bedroom window:

The patch measures 12 mm across and 14 mm tall. From across the room, it looks like a smudge, but it consists of hundreds of eggs, each on a tiny stalk glued to the glass:

The bottom image is two days later than the top one, both are scaled to about the same size and contrast. The critters look about the same, although I think the lines have more prominent ripples or bumps.
We have no idea what they’ll turn into, but they certainly look like they have two eyes and wings …