The concept of trapping vacuum-arc-generated macroparticles by a liquid is introduced. Experiments have been performed using a pulsed vacuum arc plasma source operating with a carbon cathode. Vacuum pump oil was used as the trapping liquid in vacuum. It was experimentally shown that trapping did not work as anticipated: a substantial number of particles experienced elastic reflection from the liquid surface. With simplified energy and momentum balances it is shown that the liquid behaves increasingly like a solid when the approaching particle is fast. A significant portion of its kinetic energy is transformed into deformation energy which can reappear as kinetic energy of the reflected particle. Particle reflection is likely to be additionally supported by a Leidenfrost-type effect: a thin oil vapor layer of relatively high pressure can be formed between the liquid surface and the macroparticle caused by the macroparticle’s high temperature. © 1998 American Institute of Physics.