What would be really funny is if one of them caught this "water" in their cup and drank it. It's what they deserve:
Spittlebugs are xylem parasites of vascular plants. They tap into the xylem through a proboscis, suck out the xylem sap, and absorb the nutrients within. Xylem sap is very dilute, though, and they must process a lot of the liquid sap to obtain their nutrients. The excess liquid is then excreted from the anus. As the liquid passes through the anus, the spittle bug adds silk-like protein to it. As this emerges from the anus, the spittle bug folds air into the liquid with its legs, producing the characteristic spittle that envelops the insect.heh.