Zombie file · Waterfall Entrance

Flag Zombie

Probably the reason flag waves are called flag waves.

Durabilityabout 45 peas

Speedfast

Lore

Flag Zombie often rushes out first during a huge wave, waving a flag and making nearby zombies invincible. Good thing such a scary zombie appears only during flag waves. Or rather, because it appears, this kind of wave is called a flag wave.

It takes about 45 peas to defeat. If you are not sure you can kill it in time, Cherry Bomb is usually the safest answer. If we had a flag like that, the pattern on it should probably be changed to sun.

Mechanics

Role

Huge wave core · Area invincibility

Durability: about 45 peas; fast speed.
Appears first when a huge wave of zombies is coming.
Waves a flag to give nearby zombies invincibility.
Should be prioritized; Cherry Bomb is the reliable emergency answer.

Advanced mechanics

Flag Zombie rewrites part of a flag wave into a source-removal problem. While the flag remains, nearby zombies can be invincible, so ordinary wave clearing, lock-on targeting, and splash value are all reordered around the flag source.

900 HP source target

For advanced counting, read Flag Zombie as an unarmored 900 HP source target. Do not split it into Basic Zombie's 270 HP body and 90 HP critical reserve; the practical question is how long it takes to remove the flag source, and how much value is gained when the protected wave becomes damageable again.

Because it is fast, Flag Zombie usually enters the firing line before the rest of the wave. If the lane can finish a 900 HP job before it crosses the main damage zone, sustained fire is enough. If not, continuing to pour shots into other protected targets usually wastes the flag-wave window.

H_{\text{flag source}}=900\text{ HP},\qquad T_{\text{remove}}\approx\frac{900}{R_{\text{lane}}}

The aura concentrates the wave onto the source: remove the 900 HP target first, then later fire becomes effective again.

Invulnerability aura and target eligibility

While the flag is being waved, other zombies in range gain invincibility. Read this as a target state rather than an extra armor layer: protected targets have not gained another durable layer to break through; they are simply poor damage targets while protection remains active.

This forces priority onto Flag Zombie itself. Single-target shots should be directed into the source; area damage that misses the flag and only hits ordinary targets inside the aura loses much of its value. Lock-on plants also care about this state: mechanics such as Lightning Reed actively abandon a target when it becomes invincible.

z\text{ protected}\iff z\ne f\land d(z,f)\le r(D)

Radius expansion by difficulty

The protection radius is not a fixed textual value. Current references describe it as growing from close-range, to nearby, to roughly half the field, and finally to full screen; the practical table is approximately 100 px on Easy, 300 px on Medium, 500 px on Hard, and full screen on Impossible and Unbalanced.

That changes the tactical reading directly. At lower settings, the player can still work around local protection and clear pressure outside the aura. At higher settings, Flag Zombie becomes closer to a whole-wave switch: until the source is removed, ordinary clearing is largely stopped by protection.

r(D)\in\{100,300,500,\infty,\infty\}\text{ px}

The larger the radius, the less Flag Zombie should be treated as only a durable target; at top difficulty it is a board-wide protection source.

Cherry Bomb and overwrite answers

Cherry Bomb is reliable against Flag Zombie for more than raw damage. A normal Cherry Bomb resolves in two explosion segments: if the first segment covers the flag source, it can remove the 900 HP target; the second segment then reads the area again, when the formerly protected wave is easier to damage.

CD-shroom offers a different route. If the stored area is empty or low value, loading it can overwrite the current area and remove replaceable non-boss targets such as Flag Zombie from the zombie layer. Overwrite is not damage, so it bypasses HP through replaceability boundaries rather than through force; bosses and non-replaceable entities should not be handled by the same assumption.

D_{\text{Cherry segment}}=2000\text{ ash}>H_{\text{flag source}},\qquad \Delta V\approx V_{\text{protection removed}}-C_{\text{long cooldown}}

Sustained fire races the timer; Cherry Bomb uses two-stage resolution to remove the source; CD-shroom removes the flag through replaceable-layer overwrite.

Tactical reading

Flag Zombie's core value is turning a huge wave into a temporary source-protection puzzle. Its 900 HP is not the most extreme durability in the roster, but protection distorts target choice: the sooner it disappears, the sooner the whole wave returns to normal clearability.

On entry: focus lane fire into the flag source instead of letting protected bodies distract targeting.
If damage is short: use Cherry Bomb or equivalent high-certainty burst before the aura carries the wave forward.
With a CD-shroom snapshot: if overwrite boundaries allow it, an empty or safe stored area can delete the flag layer directly.
At high difficulty: estimate it as a board-wide protection source; ordinary wave clearing loses much of its value before the flag is gone.

Interactions & counters

Cherry BombIf it cannot be killed in time, Cherry Bomb is the safest answer to its invulnerability aura.
CD-shroomArea overwrite can remove it directly before the aura keeps spreading.