Found this while digitizing old vacation photos. During a visit to Kilauea Volcano several years ago, we saw pillows of lava starting to ooze from a crack near our trail across the lava flows. The lava flowed with the consistency of toothpaste, so there was no immediate hazard although our shoe soles were beginning to create a burnt rubber kind of smell. One family member (I will let you guess which one) had a tricksy idea: pour a little of our drinking water into a nearby crack. Of course, it flashed into steam with a loud sound, making everyone within earshot jump!