Particles can be used to add blood splatters, smoke, fire sparks, swarms of bug, and countless other things as well.

local function particle_effect(pos)

   minetest.add_particlespawner({
      amount = 4,
      time = 0.15,
      minpos = pos,
      maxpos = pos,
      minvel = {x = -1, y = 2, z = -1},
      maxvel = {x = 1, y = 4, z = 1},
      minacc = {x = -1, y = -1, z = -1},
      maxacc = {x = 1, y = 1, z = 1},
      minexptime = 1,
      maxexptime = 1,
      minsize = 1,
      maxsize = 3,
      texture = "texture_file.png",
   })
end