Cactus can pop the Balloon Zombie's balloon in Plants vs. Zombies.
The Balloon Zombie floats above the lawn, allowing it to bypass ordinary ground defenses. Its balloon is the key weakness: Cactus can fire a spike that pops it, causing the zombie to lose its airborne advantage and become vulnerable to normal attacks.
This matchup illustrates how the original game gives different zombies specific counters. Cactus is not simply a standard attacker; its projectile can target the Balloon Zombie's special defense. Players must therefore include the plant when a level contains airborne threats.
Kernel-pult, Torchwood, and Repeater all contribute to damage or projectile enhancement, but none is the plant identified by the game's standard Balloon Zombie counter. In later games and modes, other anti-balloon mechanics may appear, which can create confusion with the original game's answer.