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Bloons Wiki

Coats MOAB-Class Bloons in an explosive substance that causes a large explosion when they are popped.
~ BTD6

Unstable Concoction is the third upgrade of Path 2 for the Alchemist in Bloons TD 6. It makes all affected MOAB-class Bloons create a large explosion once popped, equivalent to 10% of the health of that blimp to other blimps or 1% to bloons, without taking into account health scaling. Unstable Concoction's special chemical concoction attacks are thrown every 6.0s (every 4.8s with Path 3 crosspaths), have 3 pierce each, and a splash radius of 14. Larger Potions increases the blast radius of the concoction splash from 14 to 21 but strangely does not provide extra pierce.

Concoction explosions affect up to 30 bloons, but MOAB-class bloons consume more pierce. MOABs and BFBs consume 2, ZOMGs and DDTs consume 4, and BADs consume 10. These explosions can pop any non-camo bloon type, or camos if the original Alch was given camo detection at the time. Concoction explosions have a blast radius of 40.

It costs $2,550 on Easy, $3,000 on Medium, $3,240 on Hard, and $3,600 on Impoppable.


The Alchemist wears a completely new outfit. He no longer wears a black facemask, but instead closes his goggles and wears a white lab coat with black covered shoes. The Alchemist now carries a purple bottle of chemical concoction alongside the normal potions. There are some purple stains on the monkey's fur, which match the color of the chemical concoctions that would be applied onto blimps.


Unstable Concoction adds an additional attack that coats MOAB-class bloons with unstable chemicals that inflict explosive damage once affected blimp layers have become destroyed. The damage these explosions inflict is based on the following equations:

ceiling(n * 0.10) where n is original blimp health without scaling (concoction explosion, explodes upon destroying unstable blimp, damage to MOAB-class)
ceiling((n * 0.01) where n is original blimp health without scaling (concoction explosion, explodes upon destroying unstable blimp, damage to bloons)

Therefore, concoction explosions spawned from the following blimps inflict the following damage amounts when hit onto other blimps:

  • MOAB: 20
  • BFB: 70
  • DDT: 40
  • ZOMG: 400
  • BAD: 2000
  • Boss Bloons: 1000



Unstable Concoction fills a supporting role at dealing high damage to blimps through its unstable concoction attacks. Any blimps destroyed while under the unstable concoction status effect will explode, creating a chain reaction that creates multiple explosions on every blimp affected by the status effect. This in effect may spawn large quantities of weaker bloons, which can be used to the defense's advantage or disadvantage depending on how the Unstable Concoction upgrade is utilized. Its greatest usage is on later rounds with hyperdense MOAB-class bloons.


  • It is recommended to also purchase Faster Throwing too in combination with Unstable Concoction.
    • Larger Potions will increases both splash radius and pierce of the special Unstable Concoction attacks.
    • Crosspathing with Acidic Mixture Dip will allow additional support to nearby towers every once in a while.
  • Unstable Concoction often transforms dense packs of stronger bloons into lots of weaker bloons. Some defenses strongly favor these conditions, such as Glaive Lord against Super Ceramics (as Glaive Lord has arbitrarily high pierce but deals lots of glaive-spinning damage to nearby bloons), but other defenses may not. It is worth considering how the defense would handle children that exploded from MOAB-class bloons.
    • If multitudes of high-tier MOAB-class bloons are more difficult to handle, it is best to set Unstable Concoction on Strong.
    • If multiples of lower-tier MOAB-class bloons are more difficult to handle, it is best to ensure all Unstable Concoctions are set on First to target the smaller blimps (which consume less pierce than higher blimps).
  • To make the most of this upgrade, this upgrade must be used in conjunction with effective M.O.A.B. Class Bloon popping power.
  • One 0-3-0 Unstable Concoction costs $4620 on Hard Mode. This is useful for CHIMPS Mode when looking for a useful tower that can weaken barrages of blimps.
  • Unstable Concoction is one of the few effective ways to add rather low-cost support for beating Round 98, the others being Shattering Shells and 2-0-4 MOAB Press spam. There are advantages for using Unstable Concoction over Shattering Shells as with the other way round, but more importantly Shattering Shells will instantly weaken blimps and not leave random clumps of Super Ceramics, unlike Unstable Concoction. However, there is no harm for doing both.

Version History[]

Unstable Concoction has been nerfed considerably since it was first released, but nonetheless has always been a popular method of supportative damage in CHIMPS games while maintaining the double-edged benefit-versus-drawback nature.

  • Nerf Explosions from Unstable Concoction can no longer affect the children bloons that spawn from the exploded MOAB-class bloon.
  • Buff Unstable Concoction potions now benefit from Faster Throwing and Larger Potions.
  • Nerf Unstable Concoction explosions will now take more pierce to hit MOABs of higher tiers, 2 pierce for MOAB/BFB, 4 pierce for ZOMG/DDT and 10 pierce for BADs.
  • Buff Attack can now be thrown over obstacles.
  • Nerf Unstable Concoction explosion no longer damages Camo Bloons without the Alchemist's camo detection.
  • Nerf Unstable Concoction's % damage increases until Round 150+.
  • Nerf [undocumented] Unstable Concoction damage no longer scales with any HP multiplier, such as Double HP MOABs, Freeplay Mode scaling, and the MOAB Health multiplier in the Challenge Editor.
  • Nerf [undocumented, bug] Erroneously, concoction explosion damage from fortified blimps is calculated under the assumption that the blimp is not fortified.
  • Buff [bug fix] unstable concotion takes fortified bloon property into account again


Official artwork[]



  • This upgrade used to be one of the only upgrades that could chemically affect BADs visually, as glue did not slow down BADs, though glue can damage BADs. However, as with other MOAB-class bloons, the Unstable Concoction only works when the MOAB-class bloon layer is fully destroyed under the effect of the chemical.
    • This was no longer true as of Version 2.0, since glue can now appear on the BAD as of said update.
  • Unstable Concoction used to be able to damage spawned bloons inside of the exploded MOAB-class bloon (i.e. the exploded MOAB-class bloon can even skip MOAB-class layers), but this no longer works as of Version 3.0.
    • It was really useful against the BAD on Round 100, since the explosion from the BAD is so huge that the DDTs are completely popped and the ZOMGs are skipped to BFBs. Obviously though, good BAD-popping power is required to make Unstable Concoction really worthwhile, as the Unstable Concoction alone will not deal enough damage to BADs on its own.
  • Unstable Concoction was able to pop Camo Bloons if the MOAB class bloon was near them. This was patched as of Version 12.0.
    • This made Unstable Concoction the only upgrade to attack camo bloons without support, as an unsupported Bloon Master Alchemist cannot target camo bloons at all, including splash damage from the bloon-transformation potion.
  • Before Version 17.0's percentage damage cap nerf, it was incredibly useful on "epic late-game" Freeplay Mode, as the blimp damage caused by the explosions were able to reach extreme amounts due to the nature of percentage damage and because of freeplay's blimp health ramping.
  • As revealed on one of ISAB's videos (as shown here), on Version 17.1 (and likely also Version 17.0), there was a bug whereby boosting an Unstable Concoction Alchemist's damage via Sun Temple and True Sun God support buffs would allow the Unstable Concoction's explosions to deal extreme amounts of damage. It was highly likely that these explosion damage amounts were just exactly the amount of damage it would have inflicted on Round 150. This was fixed as of Version 18.0, and similarly was fixed for Prince of Darkness and its zombie bloon spawns.
    • Several days before then, there was a Black Border Bloody Puddles achieved by a Reddit user on r/btd6 that heavily involved the unstable explosions Unstable Concoction bug. Link.
  • Out of all upgrades in the game, Unstable Concoction is the only upgrade to always turn towards the direction of bloons regardless of where the Alchemist is or whether it is attacking or not. Further upgrades do not share this feature.