Devastatingly large explosions, and each pops though 5 layers of bloon
~ BTD5 description
Devastating explosions pop 5 layers of bloon.
~ BTD6 description

The Big One is the final upgrade of the path 1 for the Mortar Tower in BTD5. It makes devastatingly large explosions, each popping up to 100 bloons and tearing through 5 layers of Bloon. In BTD5, it costs $10,000 on Medium.

In BTD6, the upgrade returns as the fourth upgrade of Path 1 for the Mortar Monkey. The explosion radius is somewhat smaller than it was in BTD5, but now each main explosion emits an additional secondary explosion (from the Shell Shock upgrade) that can either stun non-MOAB-class bloons near the explosion epicenter for 0.5 seconds or deal 1-2 damage to bloons caught in the perimeters of the blast radius. But just like in BTD5, the main explosions can pop up to 5 layers of bloons per hit and can damage bloons with Black Bloon properties. However, the pop limit of each explosion has now been lowered to up to 85 bloons. In BTD6, it costs $8,000 on Medium.


  • This is useful if the player is facing Pink Bloons because it's strong enough to the point where Pink Bloons will be instantly destroyed the second the Mortar Tower hits them.
  • If the player buys this upgrade with Burny Stuff for both Mortar Towers on the Direct Assault mission just before round 23, they can pass the mission without spending a single dollar in Monkey Money.
  • On BTD Battles, this can be used for defending a RRROD. Note that by itself this tower cannot pop Camo Bloons, so use this with a x/3 Mortar Tower if the opponent sends Camos.
  • This is extremely useful for rounds 21 and 36 and 47 with a Radar Scanner or a Meerkat Spy on round 47.
  • This upgrade isn't really effective on MOAB-Class Bloons, as it is like a slow-firing & weaker MOAB Mauler to them. Players may want to damage them if possible.

Update HistoryEdit

Update History (Bloons TD Battles Mobile)Edit


Buff The Big One price decreased ($10000 → $6000).


Nerf The Big One price increased ($6000 → $7500).

Update History (BTD6)Edit


Buff The Big One cost reduced ($10k --> $8k)

Buff The Big One blast radius increased

Buff The Big One will now (correctly) damage DDTs when given camo detection.





  • In the Mobile version, the description originally read "Devastating explosions each pop 3 layers of bloon." (even though it still popped 5 layers). It appears that the description had an error in it. In an update, it has been corrected to 5 layers. This error still exists on the Steam version.
  • These are useful for making the game lag less because of how large the explosions are, with the huge range along with the fact that they take out more bloons instantly.
  • If the player adjusts the aim for a Mortar Tower with The Big One on the center of Mt. Magma, or the center of 3 Times Around's circle, it will cover the entire circular center.
  • This is the only upgrade to increase the popping power of Mortars. Every other Mortar upgrade has a popping power of 40, while The Big One has a popping power of 100 (in addition to popping 5 layers, meaning the Big One can pop up to 3,100 bloons in a single shot (if it hits 100 Ceramics with 1 HP left).
  • The monkey next to The Big One seems to wear the same clothes as a Glue Hose Glue Gunner, but the cloth is protecting the monkey from radioactive mortar shells and not from glue.
  • According to the upgrade picture, The Big One cannot safely be touched by the monkeys (even with gloves) without the help of tongs to insert the mortar. However the monkey is not using them in-game, so the upgrade picture could be purely for emphasis to show how dangerous The Big One is.
  • The explosion sizes are of the same of the missiles fired by a Temple of the Monkey God, which are also as big as the radius of an unupgraded Super Monkey.
  • The Big One is one of the few explosive towers that can pop Black and Zebra Bloons, the other ones being Bloon Impact, Hydra Rocket Pods, Spiked Mines, and Flash Bomb. This is because they use Bloontonium.
  • The name may have come from the NASCAR term The Big One, meaning a huge crash.
  • It takes 40 explosions to pop a M.O.A.B's outer layer using this upgrade.
  • In BTD5 Flash, it makes a louder blast sound when its upgraded to this.


  • The artwork for The Big One does not feature the radioactive symbol on the thick mortar barrel, but the in-game tower does.

Start a Discussion Discussions about The Big One

  • The Big One vs Cluster Bombs

    3 messages
    • cluster bombs maybe
    • As a “radius” goes, it is the Big One, as Cluster Bombs has some gaps in its “radius.” The Cluster Bombs and the Big One have a simi...
  • How the MOAB Assassin really works

    15 messages
    • wrote: "Facepalm" 1.3 grammar mistakes Please don't harass other people's grammar.
    • they can pop camos. They o not nee signal flare. That or I tend to use fully upgrade monkey villages too much. And grammar Nazis can screw off
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