"Stacked wilds" are wild symbols that appear stacked on top of each other on the various reels. Wild symbols can substitute for other symbols so as to form winning combinations. When stacked wilds appear on the reels, they can cover multiple reels at once, creating multiple winning combinations. This can result in players hitting bigger wins than would be the case with normal wild symbols. Stacked wilds are a popular feature in many online slots and help make a slot even more exciting and lucrative.