Windy City Aven (UNK-UU04A) - Un-Known Event Playtest Cards

Flying
Ascend MagicCon: Chicago (If you attended MagicCon: Chicago and control ten or more permanents, you get the Windy City's blessing for the rest of the game.)
Whenever this creature attacks, if you have the Windy City's blessing, create a 1/1 blue Bird creature token with flying.