Robin Hood: Prince of Thieves - Sneaky "Spit"
In the scene where the executioner is about to behead Will Scarlet(Christian Slater), the executioner ties Will down to a barrel and then "spits" on his face. If you rewind it and put it in slow-motion, you'll notice the spit never comes out of the executioner's mouth, it appears out of nowhere through digital work, then slides down the side of Will's face.
Rewind button, pause/slow motion
on 01-29-2001 and