Nova is a type of card that was planned to be included in Mayfair's Even More Cosmic Encounter and Cosmic Novas expansions. As these expansions were never released, Novas as well were never released into the game.
Rules[]
Novas would have been similar to Flares, in that they correspond with aliens and have powers based on whether or not you are the corresponding alien when you use the card. The difference between Novas and Flares is that Novas return to the hand after use, while Flares in the Mayfair edition are discarded after one use, making them similar to the flares from the Eon edition (as flares in the Mayfair edition were discarded after one use).