Balloon Zombie

Balloon Zombies float gently over all of the player's plants and can only be targeted by the Cactus and the Cattail, or blown away by a Blover.

Suburban Almanac Entry
 Balloon Zombie 

Balloon Zombie floats above the fray, immune to most attacks.

Toughness: low

Special: flying

Weakness: Cactus and Blover

Balloon Zombie really lucked out. The balloon thing really works and none of the other zombies have picked up on it.

Strategy
Use a Cattail or a row of Cacti to pop their balloons, reducing them to the state of a normal Zombie. If they are popped over a Pool lane, they will die immediately as they will drop into the water and drown. Alternatively, one could blow all of them away with the Blover; the player should wait as long as possible before planting a Blover in order to save Sun by blowing away multiple instances of them. They cannot float over your Lawn Mowers, Pool Cleaners or Roof Cleaners, fortunately.

I, Zombie
The Balloon Zombie is only available in the Dead Zeppelin I, Zombie level. Use them in rows without Cacti. The balloons will pop at the end of each row so that the Balloon Zombies can eat the brain, so sending them is not pointless. If you really want to send a Balloon Zombie in rows with Cacti, they can be removed by a Bungee Zombie. Note that Balloon Zombies will not eat Sunflowers that they fly over. It is better to send regular Zombies rather than the Balloon Zombie.

Trivia

 * The Balloon Zombie, the Zomboni, and the Catapult Zombie are the only zombies that can be killed using a single hit from a plant (except for instant kills)
 * If a Balloon Zombie is over the pool when its balloon pops, it will immediately die, disappearing instantly.
 * Like the Bungee Zombie, Zombie Bobsled Team and Zombie Yeti, when a Balloon Zombie with a balloon is hit by an explosive instant kill it does not crumble into ash but turns into a black silhouette and vanishes.
 * An inflating sound is heard before Balloon Zombies appear.
 * It is hard to believe that it inflates its balloon just before it appears instead of keeping it ready.
 * Maybe it is to not waste air.
 * The Balloon Zombie and the Bungee Zombie are the only zombies to appear both on land and in the pool.
 * The Balloon Zombie, Bungee Zombie, Dolphin Rider Zombie, Zomboni, Jack-in-the-Box Zombie, and Pogo Zombie are the only zombies that make noises before entering.
 * The Balloon Zombie seems to have a hunchback.
 * The Balloon Zombie can be killed by explosives while in the air.
 * If a Balloon Zombie is hit by a lawn mower while still on its balloon, its balloon will pop and it will turn into smoke, just like a Gargantuar.
 * However the lawn mower is too low to hit it, though the handle might have hit it, it is also too low to hit it.
 * The Balloon Zombie can be frozen while still floating if an Ice-shroom is used, but will only be slowed down.
 * The Balloon Zombie (while on its balloon), the Digger Zombie, (while digging), the Ladder Zombie, the Gargantuar, the Zomboni, and the Catapult Zombie are the only zombies that can get past a Tall-nut by themselves.
 * The Balloon Zombie, the Aquatic Zombies, the Digger Zombie, the Dancing Zombie, the Backup Dancers, the Zombie Bobsled Team, the Zombie Yeti, and every Non-Almanac Zombie are the only zombies that do not appear during the battle with Dr. Zomboss.
 * The Balloon Zombie is one of 9 zombies not allowed for Versus Mode, possibly due to two reasons: it can pass the player's plants without damage, and it only requires two to eat the brains (unless the Lawn Mower in that row has already been used, in which case it would only need one). The other unusable zombies include the Backup Dancer, the Zombie Bobsled Team, the Zombie Yeti, the Imp, Dr. Zomboss, and all three aquatic zombies (the Ducky Tube Zombie, the Snorkel Zombie, and the Dolphin Rider Zombie).
 * The Balloon Zombie is the only non-Vault Zombie that can pass every type of plant without trying to eat it.
 * This Balloon Zombie is also the only zombie that can be killed by a Blover.
 * The Balloon Zombie's balloon has an evil face-like drawing on it.
 * When the Balloon Zombie is floating, its feet are straight, but when it is on the ground, they are not.
 * The Balloon Zombie and the Digger Zombie are the only zombies that lack a shoe.