  We report on the self-propulsion of boiling droplets which, despite their
contact with viscous, immiscible oil films, attain high velocities comparable
to those of levitating Leidenfrost droplets. Experiments and model reveal that
droplet propulsion originates from a coupling between seemingly disparate short
and long timescale phenomena due to microsecond fluctuations induced by boiling
events at the droplet-oil interface. This interplay of phenomena leads to
continuous asymmetric vapor release and momentum transfer for high droplet
velocities.
