if you collect enough special symbols before they vanish.
essentially, with a walking wild you never have to pay for a spin. they are a great way of getting free spins without hitting three scatters on the reels, making them very interesting features. the combination spin which feels like never-ending spins of big prizes is extremely enticing, especially with the potential of yet another wild to hit the reels and thus extend your bonus round. even in practice mode the game is exciting! if you haven’t yet tried one of these games, i highly recommend that you do so. 