Snorkel Zombie

The Snorkel Zombie is the twelfth zombie encountered in Adventure Mode. The Snorkel Zombie is able to submerge and progress underwater in the pool, avoiding hits from all except lobbed-shot plants. They will come up to eat any plants in their way; this is the only time they're vulnerable to normal shots.

Suburban Almanac Entry
 Snorkel Zombie 

Snorkel zombies can swim underwater.

Toughness: low

Special: submerges to avoid attacks

Only appears in the pool

Zombies don't breathe. They don't need air. So why does Snorkel Zombie need a snorkel to swim underwater? Answer: peer pressure.

Overview
The Snorkel Zombie absorbs 10 normal damage shots and its appearance changes upon an absorption of 5 normal damage shots before dying at 10 normal damage shots but it does not degrade if it is killed underwater.

Appearances
Adventure Mode: 3-3, 3-4, 3-5, 3-7, 3-10

Mini-games: Zombiquarium, Big Trouble Little Zombie

Puzzle Mode: Last Stand: Pool, Last Stand: Endless

Survival Mode: all pool and fog levels

Co-op Mode: Co-op Pool, Co-op Hard Pool, Co-op Endless

Strategies
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 or killed by instant kills such as Tangle Kelps, Doom-shrooms, which are woken by Coffee Beans, and others. 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 Ducky Tube Zombies, so they shouldn't be too hard to kill, also you can use a Snow Pea to slow him down.

Zombiquarium mini-game
In the mini-game Zombiquarium, the Plants vs. Zombies version of Insaniquarium (another Popcap game), the player spends five sun to feed brains (up to three can be in the tank at a time) to the 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 Snorkel 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 don't feed them quickly.

Trivia

 * The Snorkel Zombie shouldn't be able to sink with armfloats on, but he still does it.
 * The Snorkel Zombie never appears on the fog levels of Adventure Mode. This is likely to avoid making the fog levels too troublesome.
 * Although being dead, therefore not having to breathe, he wears a snorkel, apparently due to "peer pressure".
 * The Snorkel Zombie will still do it's bubbling animation underwater even if it's in the middle of a Lily Pad.
 * The Snorkel Zombie is one of the five zombies that have eyewear, the others being the new Dancing Zombie, the Zombie Bobsled Team, the Newspaper Zombie and the Pogo Zombie.
 * It is one of the two zombies with straps on their eyewear, the other being the Zombie Bobsled Team.
 * If you kill him when he is underwater, only his head will fall off and his body will not be shown. He also does not degrade.
 * If he bites a Garlic, it will not make a disgusted face, but it will make the 'bleh' sound and move to another lane.
 * The Snorkel Zombie is the only zombie that produces sun.
 * He has an "I love brains" shirt on.
 * On the DS version, after he eats a plant, he speeds up, most likely frightened.
 * This applies all other zombies after they encounter a plant.
 * The Snorkel Zombie is one of the Zombies not allowed in Versus Mode, for an obvious reason (can't submerge in grass or pavement, so it would be senseless to have it available since Vs. Mode is always the day setting). The other zombies not available in Versus Mode are the Imp, Dolphin Rider Zombie, Ducky Tube Zombie, Balloon Zombie, Zombie Bobsled Team, Backup Dancer and Dr. Zomboss.
 * His mask has a crack on it showing his eye but underwater his eye is still open therefore he can see underwater.
 * It is unknown why the Snorkel Zombie doesn't just swim under the Lily Pads.
 * If he did swim under the Lily Pads, then he would bypass all your defenses, making the game unfair, and he would require the use of Cherry Bombs in 3-3 as it would be the only way to affect him.
 * If a Snorkel Zombie dies from a lobbed-shot plant while it's underwater, then it is one of three zombies that can die without degrading with the others being Bungee Zombie and Dolphin Rider Zombie while riding his dolphin.
 * More than often a player encountering Snorkel Zombies for the very first time will encounter numerous deaths before figuring out how to beat them. Among others two strategies to beat snorkelers without luring them up to eat something is to use a Chomper on top of a Lily Pad. A bit expensive, but highly reusable and works very well. The second strategy is to simply use a Squash on a Lily Pad.