mysterious hieroglyphics

Sunday night reading in bed, I heard a thunderous roar of a crowd of Amish youth,  after the singing at the next door neighbors,some walking past our house, some at a distance.  A primal scream?  A ritual of that gang's leaving after a day of volleyball and singing by gas lanterns?

Today a silvery marking on the zelkova tree caught my eye.  Youth on a rampage marking territory, or doing graffiti?  Some ancient spirit writing hieroglyphics as a warning, as a sign.  Or, a lost snail confused about which way is up in the dark. Or two snails' courtship, leaving their slime which in sunshine turns visible.

All speculation.