This is a New Rule you can add in to any Fluxx deck. (It is included in Cat Fluxx.)
It says, "If there's an actual, living cat in the room where this game is being played, all players draw and play 1 extra card."
This card was first included in Cat Fluxx in 2025, and created as a loose promo so people could add it to their other decks.
My cat Biscuit wanders across the table mid-game every single time, so getting an extra draw and play each turn because of it is hilarious. The rule text is short and clear enough that nobody has to stop and reread it.
We play with our cat sprawled right on the table, and this card instantly turns her napping into part of the game — everyone has to grab an extra draw and play just because she's there. It fits perfectly into our existing Fluxx setup and adds a silly, chaotic layer that keeps things moving. The rule
We added this card to our base Fluxx deck and it instantly became a house rule. The wording is simple enough that even new players get the joke right away, and it genuinely speeds up the game when our cat decides to nap on the table.