2 LARGE sponge rabbits are shown.
The chosen rabbit is placed in the volunteer's hand. The other rabbit is placed into the magician's pocket.
The volunteer opens his hand, Out pops two rabbits! Apparently the one rabbit jumped from the pocket to the hand.
Then the two rabbits are placed into the volunteer's hand. After a pause the hand is opened and this time the two large rabbits have been joined by a bunch of baby rabbits

The magic happens in the hand of the spectator! Great fun.