This are also known as night crawlers. Some people make a business out of this selling it to fisherman. If you don't water your lawn for a couple of days......they will go lower in the ground. You can ariate the soil.......and later run a roller over it to compack the dirt.....You could scoop up the dropping from them and put it in your mulch pile. They really are good for the garden just too many of them makes a mess. Encourage the birds to eat them.