Card Soldiers are characters from Lewis Carroll's book "Alice's Adventures in Wonderland." They comprise the army of King and Queen of Hearts and have playing cards for bodies.
The Card Soldiers were characters made real accidentally by the Ethereal Solidifier. After 10:30 A.M., the Ghostbusters briefly met The White Rabbit. Soon after, the Card Soldiers marched in the same direction as The White Rabbit. In fact, they marched right over the Ghostbusters without pause.