Brown to grayish, up to 2" long, a slug looks like a snail without a shell. Slug eggs are laid in jelly-like masses under debris in damp areas. Slugs live a year or more and develop slowly. In spring, they are one of the first pests to feed on seedlings and ornamentals, eating large holes and leaving a slimy trail. Slugs and snails like tender leaf growth of peas, lettuce and other greens; hostas and other perennials.