“…In contrast, droplet impact on a solid surface or a liquid pool has been studied extensively [29,36,39]. However, a granular substrate can act both solid-like and fluid-like [56] and many experiments have been conducted to reveal the response of a granular packing to a solid object impact [68,71,75,80,82,87,88], where the intruder does not deform. Droplet impact on a granular substrate adds new challenges to the above: First, both the intruder and the target, not merely one of the two, deform during impact; second, the liquid composing the droplet may penetrate into the substrate during the impact and may, in the end, completely merge with the grains.…”