  A liquid droplet hovering on a hot surface is commonly referred to as a
Leidenfrost droplet. In this study, we discover that a Leidenfrost droplet
involuntarily performs a series of distinct oscillations as it shrinks during
the span of its life. The oscillation first starts out erratically, followed by
a stage with stable frequencies, and finally turns into periodic bouncing with
signatures of a parametric oscillation and occasional resonances. The last
bouncing stage exhibits nearly perfect collisions. We showed experimentally and
theoretically the enabling effects of each oscillation mode and how the droplet
switches between such modes. We finally show that these self-regulating
oscillation modes and the conditions for transitioning between modes are
universal for all tested combinations of liquids and surfaces.
