Why is a slugs slime glittery? i sat on one lastnite wen drunk n it was glittery on my trousers!?

Hi there... the shiny/glittery slime trails slugs leave behind in their travels is caused by mucous. The mucous not only allows them to move, it prevents the moisture in their bodies from drying as they move over soil. Slugs sometimes follow their slime trails from previous nights, and sometimes follow other slugs’ trails who, in turn, follows theirs.