And Then There Were Four from Magic by Gosh (Black)

A spectator holds onto a sponge cube in his closed hand. The magician touches the spectator's hand with a coin and the sponge multiplies into two sponges! Both of the sponge cubes are again held by the spectator, and with another touch of the coin they impossibly multiply again into three cubes! All three cubes are then clearly placed into the spectator's hand and the magician asks, "Would you believe that now there are four?" He touches the spectator's hand with the coin again and this time when the spectator opens their hand, instead of four small cubes it's one large four!

Includes all the necessary sponges.

Note: Also available in red