Brickhead Zombies and their world-themed versions in Plants vs. Zombies 2 are basic Zombies with armor on their heads, greatly increasing their toughness.
However, unlike Knight Zombie, Blockhead Zombie and Jurassic Fossilhead, these are Veteran Zombies, which are upgraded versions of Buckethead Zombies that only appear in levels of world expansions. They have higher health as well, and now absorb a total of 2390 damage, withstanding 120 pea shots and being approximately 1.85 times stronger than Buckethead Zombies.
Mammoth-Head Zombie in particular is a bit different from the others, having higher HP (3270, as opposed to 2390), slight resistance to non-fire elemental attacks and a 50% chance to be immune to insta-kills.
Brickhead Zombie's Almanac entry references the classic fairy tale The Three Little Pigs.
Amberhead Zombie's almanac entry references the movie series Jurassic Park, where humans revived dinosaurs via DNA extracts found from a mosquito trapped in amber.
Appearance
Brickhead Zombies are somewhat unique compared to other headwear zombies. Their headwear usually covers the rest of their face, while also showing the eyes for them to see. Amberhead Zombie and Holo Head Zombie may have their faces shown, but it is slightly modified and its jaw does not move due to being part of the head sprite. All variants when they are on their third degrade will show the rest of their faces.
Almanac entry
Brickhead Zombie
Brickhead Zombie
TOUGHNESS
Machined
SPEED
Basic
Brickhead Zombie's brick head provides thorough brickheaded brickheadness.
After consultation with various storybook wolves, it was determined that straw helmets and wood helmets were not up to snuff, and that brick helmets had to be seriously considered.
Pyramid-Head Zombie
Pyramid-Head Zombie
TOUGHNESS
Machined
SPEED
Basic
His pyramid-shaped headgear provides triangular noggin protection.
Pyramid-Head Zombie isn't aware that his pyramid is pyramid-shaped. He's a little slow in that respect.
Barrelhead Zombie
Barrelhead Zombie
TOUGHNESS
Machined
SPEED
Basic
Barrelhead Zombie's keg-like hat provides augmented protection.
Dredged from the deepest of seas, Barrelhead Zombie's barrel is a high-quality cask that fits just a bit too snugly.
Cart-Head Zombie
Cart-Head Zombie
TOUGHNESS
Machined
SPEED
Basic
Cart-head Zombie's cart-shaped chapeau provides extra-wheeled head protection.
Cart-Head Zombie could probably move a lot faster if he did a handstand and rolled, but he's not thinking that far ahead.
Holo Head Zombie
Holo Head Zombie
TOUGHNESS
Machined
SPEED
Basic
Holo Head Zombie's head mounted force field provides hyper-protection.
The force field gets a unique color from frequency harmonics and a liberal dose of purple paint.
Amberhead Zombie
Amberhead Zombie
TOUGHNESS
Machined
SPEED
Basic
Amberhead Zombie's head-engulfing ball of amber provides hardened protection.
If you were to extract DNA from the Amberhead Zombie and combine it with the DNA of a frog, you'd be breaking the law at some point.
Bust Head Zombie
Bust Head Zombie
TOUGHNESS
Machined
SPEED
Basic
A bust head means this Roman zombie can take a serious beating.
Bust Head Zombie belongs in museum with a big sign that says something like, "WARNING: THIS IS A ZOMBIE!"
Overview
Brickhead Zombie and his versions absorb 2390 damage, withstanding 120 pea shots, and their appearance change upon absorbing 700, 1450, 2200, and 2295 damage before dying at 2390 damage.
Brickhead Zombie and his variants can take quite a beating, so resort to instant-kill plants to take them out. Grimrose is effective at taking them out, but against groups of them, use area of effect plants like Cherry Bomb, Grapeshot, Primal Potato Mine, and Potato Mine, all of which ignore armor. If there are only a few, try not to resort to insta-kills but instead let heavy artillery plants such as Winter Melon or Banana Launcher take them down. You could also use Primal Peashooters to stall them as they take in damage.
Grinderhead Zombie is a zombie that appears in Thymed Events, specifically the Backyard Big Top event. He is identical to other Brickhead variants, but releases a Zombie Monkey as soon as his headgear is destroyed. The monkey is as fast as a Zombie Chicken and is able to absorb 300 damage before dying, equivalent to that of a Zombie Parrot
Nutcracker Zombie is a zombie that appears in Thymed Events, specifically the Feastivus and Mega Gatling Pea's Winter Adventure events. His total health is identical to other Brickhead equivalents. He is immune to various sources of knockback, and can perform a nut chop attack that deals 50% max health damage to certain nut plants.
Castlehead Zombie is an unused zombie found in the files of Plants vs Zombies 2. It was originally going to be part of the unreleased Dark Ages expansion levels. This zombie acts exactly like a Brickhead Zombie, with no other special abilities.
As the name suggests, this zombie's form of protection comes from its castle brick helmet, with a tile roof and spire on top. The only time this zombie was ever seen in-game was from an ad for a Penny's Pursuit event named Darker Ages.
Although having previously thought to be scrapped, the sprites for this zombie were suddenly re-added to the game's files in the 10.4 update, meaning he may actually be re-implemented after going unused for several years.
Gallery
Plants vs. Zombies Wiki has a gallery for Brickhead Zombie.
The Brickhead Zombie variants have a health close to Robo-Cone Zombie, each one absorbing only 110 damage less than a Robo-Cone Zombie.
Like most veteran zombies, Brickhead Zombies and their variants do not appear in Endless Zones.
All Brickhead variants' (except for Pyramid-Head and Bust Head) Almanac entries start with their first names, which is quite different from other entries since a zombie's Almanac entry will usually start with their pronouns such as "he," "their," "its," and etc. Only plant Almanac entries would usually use a name for the beginning of their entries.
Excluding Nutcracker Zombie and Mammoth-Head, all of the Brickheads' internal names end with the suffix _armor4.
This, Rodeo Legend Zombie, and Imp Dragon Zombie are the only zombies to appear only in a boss fight in a specific world. This is because the expansion levels the aforementioned two appeared in were moved to epic quests, but they also appear in Modern Day - Day 32 in the Wild West battle.
Specific to Holo Head Zombie
Prior to version 6.0.1, when a Holo Head Zombie got ran over by a Lawn Mower, its force field, arm, and head would fall off separately, but another head would still appear to be encased in the force field. After that update, the force field is in its final degrade when hit by a lawn mower.
This is because Holo Head Zombie's force field sprites have the head inside it.
The same also happened when he was killed by plants such as Shadow-shroom, where its arm, head, and force field fall off and another head is still encased in the force field.
Additionally, when he was killed by explosive plants and Electric Blueberry, he burned into ashes, but another head still appeared to be encased in the force field.
A similar glitch happened to the Excavator Zombie; its shovel falls off, but the body will still be holding another shovel.
Mammoth-Head was originally meant to be used in a Frostbite Caves expansion for the international version, but was scrapped before being re-used for Frostbite Caves Resurgence with an updated design.
Strangely, Mammoth-Head's codename is iceage_armor3_elite, implying that he's an elite variant of Blockhead Zombie, despite not having any attributes of an elite zombie and visually clearly being a brickhead.