Any idea what did this?

[driverrob]

Some extremely small animal had left this trail on the misted up inside of the garage window this morning. There were other, smaller trails elsewhere on the window. This area is about 10x12 cm and the trails are a fraction of a mm wide.

[driverrob]

AdiT said:

Snail/slug thats freshly hatched.

That's what someone suggested on FB but the trail's ends are on the glass. ??