Snorkel Zombie

Snorkel Zombies are zombies able to hide underwater in the pool, avoiding hits from all but lobbed-shot plants. They will come up to eat any plants in their way.

Strategy
Aside from forcing them to come up to eat plants, there are several ways to kill Snorkel Zombies; they can be hit while underwater by lobbed-shot plants still or killed by Instant Kills such as Tangle Kelps. The easiest way to combat them is by placing a Wall-nut, Tall-nut, or Pumpkin on a Lily Pad. When surfaced they act like regular zombies, so they shouldn't be too hard to kill.

Zombiquarium Mini-game
In the Mini-game Zombiquarium, the Plants vs Zombies version of Insaniquarium,(another Popcap game) the player spends 5 Sun to feed Brains (up to three can be in the tank at a time) to Snorkel Zombies, which produce Sun in turn. The player can also use Sun to buy more zombies or to buy the Trophy and win the level. Just make sure to feed the zombies every couple of minutes; to tell when they are hungry you can keep a brain floating in the tank and wait until they swim towards it. They will turn green when they get hungry and will die if you do not feed them quickly.

Trivia

 * If you have a hypnotized Ducky Tube Zombie about to go up to the surface, and a Snorkel Zombie runs to the pool, the Snorkle Zombie will not eat the Hypnotized Zombie and will die as the hypnotized Zombie eats the other Snorkel Zombie.
 * The Snorkel Zombie should not be able to sink with armfloats on, but still he does it.
 * This is also accompanied by the Snorkel Zombie not having a death animation while on land.
 * It is possible that this is because the game developers did not program it as they did not think a Snorkel Zombie could die that way, or they decided to ignore the whole fact in all.
 * It Is unknown how the Lobbed-shot plants know where the Snorkel Zombie is despite the fact it can't be seen. Although, the Lobbed-shot plants may be like the Chomper, who can sense Zombies in front of them.