There's something about zombies in Minecraft that if you merely drop them down 23 blocks for the fall damage, they take two punches to kill, rather than one punch like other mobs. (23 ½ is the same, and 24 blocks will simply kill them.) I’ve heard that this is due to zombies having “armor” (not visible armor, evidently) that has to be broken first (or perhaps it has something to do with the effects of rounding on armor damage reduction).

How can I automatically soften up the zombies a little bit more so that they only take one punch to kill, preferably in a way which ends in a drop of at least 11 blocks?

The mechanism must be fully automatic and accept zombies arriving through a water stream. It's OK if the occasional real-visible-armor-carrying zombie still takes extra hits.

What doesn't work:

Fall damage and suffocation damage seem not to be able to “remove the armor”: I have not found any combination of two falling stages, or 1 tick of suffocation followed by falling, which will result in a one-punch kill. (If you have found such a combination then I'd love to see an answer with a complete design to demonstrate it!)

There is the possibility of dropping mobs through lava, then water, which seems like it should work, but has the disadvantage that in order to prevent the mobs from swimming up in the liquids (thus dying to lava, or getting stuck in water), a simple tube would have to have, in order: a long drop, a lava block, (another long drop? not sure), a water block, and finally another long drop to the collection pad. This extreme height would make my underground zombie trap's plumbing poke up into my above-ground buildings.

  • Have you tried lava?
    – user28379
    Jan 20, 2013 at 19:00
  • 2
    Posting here as this is untested, but you can try a two-stage falling trap. Have the zombie fall a certain distance to get rid of its armor, land on a pressure plate which triggers a piston to push it into another fall.
    – Yuuki
    Jan 20, 2013 at 20:32
  • 2
    Never heard of zombie armor, but suffocating them with pistons usually does the trick
    – Domocus
    Jan 20, 2013 at 20:39
  • @Domocus Tried that, and it doesn't seem to work (perhaps because suffocation ignores armor?), and is also tricky to do consistently on a continuous stream of zombies.
    – Kevin Reid
    Jan 21, 2013 at 3:15
  • @JeffreyLin I'd love to see an answer containing a mechanism for reliably applying a precise amount of lava damage to mobs. Fire might be an option too.
    – Kevin Reid
    Jan 21, 2013 at 3:16

5 Answers 5


I have invented a solution to this problem using a mechanism to apply one tick of lava damage. It occurred to me that a tripwire could be placed immediately above lava in order to remove it (using a dispenser) as soon as a mob hits it, thus preventing the mob from continuing to swim in it. Doing this for the water as well as the lava means that no acceleration is needed to make sure the mob will fall down, so the whole mechanism is only a little bit of extra height above a standard fall-damage trap.

enter image description here

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Build details, from top to bottom:

  • The zombies are pushed by water into the drop pipe. I don't know how important the length of the upper section is.

  • The water and lava mechanisms are identical:

    • Each dispenser contains an empty bucket.

    • All pistons are sticky.

    • The tripwire above the fluid is the input to the left (in first image) piston monostable (rising edge detector), which causes the dispenser to remove the fluid into the bucket. The monostable ensures that the tripwire input will not interfere with the second fluid-restoring pulse.

    • Behind the dispenser is a comparator followed by 2 blocks of redstone wire; this detects the dispenser having a lava bucket (which counts as 1 stack) instead of an empty bucket (which counts as 1⁄16 stack), and triggers the right piston monostable to remove the fluid. In the event that the state of the dispenser gets reversed, this circuit will simply not generate a pulse, thus correcting the problem.

  • Below the water block is exactly 19 ½ blocks of empty space (counting the sign) down to the fall-damage landing platform.

Results: When the zombies hit the platform, a few still take 2 punches, but most of them take 1 punch to kill. I have successfully operated this mechanism in my survival world fed by two zombie spawners.


  • The amount of damage done is not completely reliable.

  • It is possible for the dispensers to get inverted (resulting in zombies falling on fire, without taking any lava damage, or from the wrong height). This latest revision with comparators can self-correct this problem, but it still may result in an occasional zombie with the wrong amount of health. (I have also seen a dispenser completely fail to respond to pulses, so I suspect there is a Minecraft bug involved.)

I know it can be hard to build mechanisms from screenshots, so if you would like any further explanation of other camera angles, feel free to ask me to add them.

  • Did my comment inspire this?
    – user28379
    Mar 31, 2013 at 20:18
  • @jeffreylin_ Can't say; I've been occasionally pondering this problem for a couple months, and I of course read all of the previous comments.
    – Kevin Reid
    Mar 31, 2013 at 20:23
  • Whew, finally got most of the bugs out.
    – Kevin Reid
    Apr 2, 2013 at 3:28
  • You can also use a bucket of lava in a dispenser: one pulse to dispense lava, one pulse to suck it back up. Timing as quick or slow as you like. (Not my original idea: this grinder style is credit to kingdaddydmac on YouTube, from one of his many Let's Plays.) Apr 2, 2013 at 3:51

From what I gathered from reading a couple of forum posts/threads, 23 ½ is your best bet. Some of the zombies will die from the fall damage but the majority should end up being a one hit kill.

This seems to be because of a change between 1.0/1.1 that added "natural" armor points to zombies, here's the code from 1.1 ( Source ) :

public class EntityZombie extends EntityMob
        public int getMaxHealth()
                return 20;

        public int getTotalArmorValue()
                return 2;

Hope this helped you, good luck!

  • I'm afraid your proposal does not work. I have tested the fall damage approach — there is a height at which all zombies die, and a height just adjacent at which they take two hits to kill. Perhaps this is because fall damage is a damage type not absorbed by armor. Thank you for adding the info that zombies really do “have armor”, though.
    – Kevin Reid
    Jan 21, 2013 at 3:13
  • Another way to go about this is go to the height where they take 2 hits to kill and just use a wooden sword, then they will only take one hit.
    – Grakiao
    Jan 21, 2013 at 3:14
  • 3
    Of course, you could just amass several of them at 2 hits and use a splash potion of healing to kill them all.
    – Unionhawk
    Feb 4, 2013 at 23:55

Mechanism above is good to expose 1 tick of lava damage, however you ALSO need precision for the falling zombies. That device can have multiple zombies falling together each with "overlapping" parts of their bodies say the feet of 2nd zombie overlapping with head of first zombie, so ONLY the first zombie takes the lava damage.

So you need to make sure ALL zombies fall either totally separately (very hard) or as a single group that are all EXACTLY at the same Y elevation.

So INSTEAD use a long-delay clock to send a "start" signal at regular intervals.

Right under the spawning rooms, some (to be found) height above the water+lava device, you have a "trap room". Zombies fall from above from a hole in roof, onto the floor, and mass up there.

All signals go from the precise "start" signal, which repeats say every 10 seconds (or whatever).

Start signal activates a piston to close the traproom roof leaving exactly a 1x1x2 high room for the zombies. Thus, no more zombies arrive (for this "wave").

Small Delay. This makes sure all zombies in room are all on trap room floor, at EXACTLY the same height. well, some might be trying to "jump around" so this ain't 100% perfect. But at least the height difference of overlapping zombies is kept limited to a minimum (aboie distance between a zombie head and roof, only a few texture pixels, compared to before where a "train" of falling but overlapping zombies had no theoretical limit on it's total height length).

2nd piston opens floor, all zombies drop.

Small delay, 2nd piston closes floor and 1 tick later, ceiling piston opens roof for starting amassing the zombies for the next wave.

Then some falling distance = that yields a SPECIFIC falling time.

Then some other delay = activates the water+lava damaging device. NO STRING WIRE necessary, the delay can be directly from the start signal not from the falling zombies. That is in fact better because... zombies jump around, right ? A precise clock is thus better. More precise and thus more controlled device.

That way, ALL zombies will take the same exact same amount of lava damage. Well, theoretically possible that the SMALL vertical distance between zombies that were flat on the trapdoor floor vs zombies that were jumping right when the trapdoor opened, is sufficient to allow a zombie avoiding the 1 lava damage (I seriously doubt it), but that should either be a VERY rare occurence, or else just try another falling height / redstone delay combination. Or just try exposing the zombies to MORE than 1 tick of lava. After all, the zombies have a "cooldown" time between damage, so making tem exposed for more thna 1 tick but way less than the cooldown time, will allow even the "slightly latecomer" falling zombies (beause they jumped right when the trapdoor opened) to "catch up" to the others and thus ALSO take the 1 point of lava damage, while the "falling normally" zombies will still be in damage immunity cooldown.

Ergo, ALL zombies take exactly 1 damage in a VERY predictable fashion.

Then some falling distance for enough falling damage so that 1 punch kills are always the case (well, zombies without actual armor equipped, that is).



You can keep the zombie suffocating for exactly 8 seconds and it will be a one punch kill (Minecraft 1.7.8).


Try to do 24 blocks but the 24th block is a fence which shouldn't kill them and shouldn't have them at two punches it should be a 1 punch kill

  • "Try"? "Should"? Have you tested this, or is it just guessing? Mar 9, 2015 at 4:22

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