that are well done,
making the impossible,
look like it could happen,
like a glass of milk that looks normal, then magically the glass becomes water, leaving the milk standing, the water effect looks so real,
the above video was made by Mainframe, a company that specialises in promotional videos,
like this one,
made for Harrods, and no I am not connected in any way with the company, I just think this type of thing is so neat.