Strange trails on pool cover

[Designer]

Yesterday morning we had heavy dew. I noticed some strange "trails" on the pool cover. I have no idea what may have made those trails, but just guessing earthworms? There was no animal present when I was there taking a picture. You can see bunny tracks in one frame for comparison.

 

[Hunter58]

Looks like snail tracks or slugs to me.

 

[Designer]

Sure could be. I've not seen any.

 

[BillM]

Whatever it is it has an extremely poor sense of direction. That rules out aliens

 

[Derrel]

Slugs is my guess.

 

[mmaria]

love the colors of the leaves here

 

[Actinia]

Almost certainly snails. They must have some sense of direction, since they have all cleared off and hidden before morning!