The spittlebug is an insect that creates its home out of liquidy foam on the stems of the herbaceous plant on which they feed and live. One may encounter gobs of sticky bubbles as it's smeared on their legs as they run through meadow grasses in the springtime. These gobs come from the little pale whitish-green spittlebug.
A member of the insect order Homoptera, the spittlebug has adapted mouthparts that pierce stems and suck plant sap. It drinks this watery, sugary sap which contains hardly any nutrients, therefore, it must consume enormous amounts to get any benefit from it. Hence, most of the sap must be excreted as waste.
When this waste is excreted from the spittlebug's anus, it mixes the material with glandular secretions to make it thicker and stickier, and with a special tubular organ on it's abdomen, it blows bubbles with this mess. It covers itself with a droplet of this material creating its house. The spittle house protects the nymph from desiccation and from predators.