What's that slime snails & slugs leave behind them for?

Question

What's the purpose

Answer 1

So they can find there way home and warn others of their territory, seems slugs are very aggressive, I'd think another reason would be for mating (in season) contained within the slime (scent)

Answer 2

YOU KNOW WHEN YOU LOOK IN THE SKY AND SEE AN AIR PLANE TRAIL, WELL ITS THE SAME FOR SLUGS AND SNAILS, ITS THE FUEL THEY BURN OFF COS THEY MOVE SO FAST,BUT LATELY WITH THE PRICE OF FUEL YOU WILL SEE A REDUCTION IN SLUGS NOT SNAILS THO THERE DIESEL.

Answer 3

It is all over their body, and is primarily for...protection, it doesn't look like it but it is huge armour, they can slither over a razor blade with no problem. I think it attracts mates as well