From Looney Labs webstore:
This is a New Rule card that works in any Fluxx deck. It is included in Fluxx Special Edition.
It says, "Play all but 1 of the cards in your hand during your turn. Draw an extra card if you started with none, and only drew one."
This card was first included in Fluxx Special Edition (for mass market) in 2012, and created as a loose promo in the spring of 2014 so people could add it to their other decks.