This card gives you a similar victory to "Final Countdown" because when 20 turns passes "Balloon Lizard" inflicts 8000 damage and Final Countdown ends in 20 turns as well. However, with "Lizard", only your turns count whereas also your opponent's turns are considered as well for the victory condition of "Final Countdown".
This card's effect, given this card's name is based on the real concept of blowing a balloon up. As someone pumps more air into it, it grows bigger (1 Counter during each of your turns.) Eventually, whether it be excessive air or an external force on a small area of the balloon, it pops (this card volleying Effect damage when destroyed.)