Snails apparently vary in size, from the size of a large real-world snail to the size of a house. A group of Snail Ladies appear in the episode, "Slow Love," attracted by Snorlock's beatboxing and sword swinging.
The Slugs are massive slugs that are found in the Grass Lands. They are extremely similar to the Snail People, except that they do not have shells. The only known slug people are both a lime greenish color, similar to the slime trail that snail and slug people leave. Slug Lady wears two bows of similar color to her skin around her eye stalks, and as a result the Slug People are considerably more simple in palette than the Snail People.