The White Rabbit is a character from Lewis Carroll's book "Alice's Adventures in Wonderland." Alice followed him down a rabbit hole to Wonderland.
The White Rabbit was another character made real accidentally by the Ethereal Solidifier. At 10:30 A.M., after the Ghostbusters vanquished Rumplestiltskin, the White Rabbit appeared, declared he was late, and ran off in a rush much like the story he was from. Soon after, the Card Soldiers marched in the same direction as the White Rabbit.