Effect:
The illusionist helps his assistant into the box, and closes up the front and top as she waves goodbye. She presses her face and hands against the stretchy fabric walls, then pushes out a silk handkerchief along with her hand, through the hole in the lid. The illusionist pulls on the handkerchief, to find it is tied to another, then another, and another- each longer and bigger than the one before. Soon he pulls out the assistant's costume, then bra, then panties, all tied to the middle of the chain of silk. She presses her hands and face against the stretchy walls, showing she's still in there, and reaches out with her arm up to the elbow, grabbing for her panties, but the illusionist pushes her hand back down, before pulling out more silk. Her face and hands stop pressing against the fabric as the silk comes out the color of her hair, then skin, then- his boxers?! He pulls the front of his pants forward and looks down, double-takes, and yanks the boxers off the chain of cloth, stuffing them down his pants before continuing to pull the last bit of cloth from the hole in the lid.

He reaches up and removes loose pin hinges on the corners of the box, then pulls the lid off, letting the sides fall flat and showing an empty table. To prove the effect, the cloth draped around the very thin table is pulled off, showing there is no place for the assistant to hide- she has vanished completely!

Or has she? With a shout, she reappears from the back of the theater, then runs up to take her bow.

Method:
There are rollers concealed inside the table beneath a trap, and a collapsible Lycra/spandex pocket under the table, which conceals the underside of the rollers and holds the extra silk required for the illusion. A hole in the table lets the assistant reach the cloth and get the trick started.

Once the illusionist closes the front panel, the assistant opens a trap in the table, and secures two cloth loops around her ankles- connecting her to the daisy-chain of silk that will be pulled out of the box. She then pulls the first silk handkerchief through the hole and hands it to the illusionist.

As the illusionist pulls the silk out, he triggers the rollers, which activate to pull the assistant between them, pressing her flat, and storing her inside the Lycra pocket. The business with the boxers covers the last bit of her compression, allowing her to be removed right in front of the audience's eyes, tied to the end of the cloth, before the illusionist collapses the box showing she's "vanished."

The girl that appears in the back of the theater is a body double dressed in an identical outfit.

(Note to self- this may get expensive in terms of assistants; save for special shows.)