Digger Zombie

The Digger Zombie is a Zombie that digs beneath the yard using its Pickaxe, eventually emerging on the left side of the lawn to attack your Plants from behind. He wears a helmet to protect himself. It pauses for a few seconds after resurfacing before proceeding to eat your Plants. It is not present on Roof levels, as there is no soil to dig through, but does appear nonetheless on XBLA/PS3's Co-op Roof level. Without advance preparation, they have the potential to do devastating damage to rows of Plants. It is first encountered in the Fog levels. Note that as it eats the Plants from left to right, it never makes an attempt to get into the Homeowner's house, except if its pickaxe is stolen by a Magnet-shroom. This may be because when they stand up, their eyes are rolling so they may be confused and feel dizzy. It is the 18th Zombie encountered in Adventure Mode.

Suburban Almanac Entry
 Digger Zombie 

This zombie digs to bypass your defenses.

Toughness: medium

Speed: fast, then slow

Special: tunnels underground and appears on the left side of the lawn

Weakness: Split Pea  and Magnet-shroom

Digger Zombie spends three days a week getting his excavation permits in order.

Overview
The Digger Zombie absorbs 15 normal damage shots and its appearance changes upon an absorption of 2, 4, 5, when the digging helmet is destroyed, and 10 normal damage shots before dying after 15 normal damage shots.

Appearances
Adventure Mode: 4-6, 4-7, 4-10

Puzzle Mode: Can You Dig It?, Three Hit Wonder, All your brainz r belong to us, I, Zombie Endless, Last Stand: Fog, Last Stand: Endless

Survival Mode: Survival: Fog, all Survival (Hard) and Survival (Endless) levels (except Roof)

Co-op Mode: Co-op Roof, all Co-op Hard levels (except Co-op Hard Roof), Co-op Endless

Others: Vs. Mode

Strategy
You can use Magnet-shrooms to steal the zombie's pickaxe so it cannot dig. When a Magnet-shroom steals it's pickaxe, the Digger Zombie will pause, a question mark will appear over its head, and he will surface and advance as usual. But however, this is not a valid strategy against it if you are solely picking a weapon against it, as it sometimes, especially in Survival (Hard), there is a possibility of it bypassing as the Magnet-shroom recharges, and it has the chance to cause it to eat your brains if it steals its pickaxe when it transverses behind your main attacking forces. Also, try using Potato Mines, as they explode if he digs underneath them. However, make sure they are armed, or else they will be eaten. Alternately, place Gloom-shrooms or Spikerocks at the back of the lawn, or use Split Peas, Starfruit, and/or Cattails to kill it if it reaches to the left side of the lawn. You can also use Pumpkins on your back row allowing your other plants more time to kill it. Instant kills, especially the Jalapeno, are good in emergencies. A Magnet-shroom that has just refreshed may snatch the Digger Zombie's mining pick while it is in the middle of your Plants, forcing him out of the ground in an inconvenient location. Before you have the Pumpkin, you may want to put Wall-nuts at the back. Having a Pumpkin, Ice-shroom, or Jalapeno available can counter this situation. In Survival: Endless (or similar levels with many Digger Zombies), the Gloom-shroom (you can use only two to save space for other plants) or Spikerock setups are the best to take care of them, because your Magnet-shrooms,Split Peas, Cattails, and/or Starfruits won't be able to keep up, making them almost useless and creating a necessity to remove them, and saving space. Note that explosive Instants can kill Digger Zombies while they are mining, so Doom-shrooms make very short work of them due to the large area, although other Instants kills like the Squash, do not work while they are underground. However, the easiest (but slowest) way to take care of them is to use Potato Mines, due to them exploding as soon as a Digger Zombie goes beneath one, and how they can be set up in advance. Also, if a Chomper is planted on the square one emerges from, it can eat it.

I, Zombie
In I, Zombie, you can use this zombie to destroy lanes that have no offensive Plants that attack other lanes or backwards (Threepeater, Starfruit, Split Pea), although inconvenient, they can still be used in these rows. Rows with Squashes, Magnet-shrooms, or Potato Mines are effectively impervious. Make sure that there are no Magnet-shrooms near it too. They can survive a Starfruit in column two from the left or a Split Pea in column 1 from the left.

Trivia

 * The Digger Zombie can lose either its left or right arm. It just depends on which way it's going.
 * Also, when the Digger Zombie is not facing the lawn, his left leg is twisted and has a shoe.
 * When digging, the Digger Zombie is the fastest zombie in the game with the exception of a Dolphin Rider Zombie that still has its Dolphin. But after finishing the digging, he is the second-slowest zombie in the game behind the Trash Can Zombie (slowest).
 * The Digger Zombie's health is on the low end of the zombies with medium toughness, with the Catapult Zombie's health being at the high end.
 * In the DS version the Digger Zombie has a weird hitbox as when he stands on a Spikeweed he doesn't react until near the edge when eating a plant.
 * The Zomboni, the Digger Zombie, the Zombie Yeti, the Catapult Zombie, Bungee Zombie, Balloon Zombie, the Gargantuar, the Giga-gargantuar and the Imp are the only Zombies that have their body shape when they get blown up.
 * Even after the Digger Zombie surfaces, a Magnet-shroom can still steal its pickaxe, which is bad as the Magnet-shroom has to refresh (although it's good in I, Zombie).
 * The Digger Zombie (if he reaches the left side of the lawn by digging), the Zombie Yeti, the Bungee Zombie, the Catapult Baseball Zombie, the Target Zombie and Dr. Zomboss are the only zombies that don't target your house.
 * The Digger Zombie is the only zombie that will not change directions when in contact with a Hypno-shroom, it will simply continue going forward when hypnotized, unless the the player steals its pickaxe while it is digging.
 * The Digger Zombie doesn't make a zombies disgusted face when biting a Garlic, instead a zombie's disgusted sound is heard while the Digger Zombie changes lanes.
 * The Digger Zombie's helmet is available in the Xbox Live Marketplace as a hat for your avatar. It costs 160 Microsoft Points.
 * The Digger Zombie can eat defensive plants with ladders on them, as the ladders are on the opposite side from it.
 * The Digger Zombie arguably has a softer side to him.
 * He has a penchant for pink tricycles in the music video Zombies on Your Lawn.
 * He usually doesn't eat the owner's brains, he only eats the plants of the owners.
 * Along with Newspaper Zombie, he is one of the two Zombies that can have a question mark over their head.
 * But in the mini game Zombie Trap if a zombie attracted to a brain gets too far away from the brain the zombie will have a question mark on the zombie's head and walk towards the house.
 * The Digger Zombie, the Snorkel Zombie and the Balloon Zombie are the only zombies that lack a shoe. This, however, excludes Zombie Yeti, Jack-in-the-Box Zombie, and Imp (who don't wear shoes). This is also assuming Dr. Zomboss wears both shoes, as his feet are not visible.
 * When the Digger Zombie dies when leaving the house, its head will fall off facing the opposite direction. This also happens to the Zombie Yeti when it is running away.
 * The Digger Zombie has overalls and a red shirt similar to Nintendo's mascot, Mario.
 * The Digger Zombie has five weaknesses, the Split Pea, the Cattail, the Starfruit, the Gloom-shroom and the Magnet-shroom (Instant-kills not included).
 * The Digger Zombie's helmet has a light on it until it absorbs four normal damage shots, after which the light will be destroyed.
 * Even while underground, the Digger Zombie will still scare the Scaredy-shroom.
 * This could possibly be because the Scaredy-shroom is afraid that the Digger Zombie might come up.
 * This is the only Almanac zombie that doesn't appear in any Mini-game and Cancelled Mini-game.
 * In I, Zombie, Digger Zombie first appears in Can You Dig It?.
 * The Digger Zombie, Zomboni, Bungee Zombie, Dolphin Rider Zombie, Balloon Zombie, Jack-in-the-Box Zombie, and Pogo Zombie are the only zombies that make noises before entering.
 * A bug in the DS version of Plants vs. Zombies is that if a plant is on the left-most block on the lawn and a Digger zombie (Facing the right) eats the plant, the Digger zombie will walk towards the right but still eat the plant and make the eating noise. This is the only way a zombie can walk and eat a plant at the same time.
 * The Digger Zombie doesn't appear on the roof, because it is impossible to dig through the panels. The other zombies that don't appear on the roof are Dancing Zombie, Backup Dancer and Zombie Bobsled Team.
 * However, Digger Zombie, Dancing Zombie and Backup Dancer appear in Co-op Roof with unknown reason.