Now send the bag with the other marble inside somewhere. Across the country, to the ISS, to Mars, next star system, where ever.
Now pull out the marble in your pocket. If it's red, the other one must be black, and vise versa. However far they are apart.
Replace marbles with particles, and colors with spins.
You have been able to determine the other particle's properties instantly over vast distance, yet you have not transfer any information.