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Extra deadly spikes can pop through 2 layers per spike and last another round.
~ In-game description

Deadly Spikes is the Tier 4 upgrade of Path 3 for the Spike Factory in Bloons TD 6. It increases the spikes' damage from one to two, effectively doubling its popping power. Additionally, all spikes now last for 3 rounds instead of 2. Like Long Life Spikes, spikes dispensed from Deadly Spikes last for 140 seconds.

This upgrade costs $2,975 on Easy, $3,500 on Medium, $3,780 on Hard, and $4,200 on Impoppable.



Deadly Spikes causes the Spike Factory to grow taller and noticeably more cylindrical; the area around the port is colored grey, then beneath that yellow, followed by the bottom being blue with a grey band sporting four gears along it. The feet, which remain yellow, extend slightly to reach this band.

The spikes are now roughly cube shaped with four grey spikes sticking out of several faces.

Crosspathing with path 1 adds a red, then grey segmented rim around the port, and White Hot Spikes specifically turns the spike tips yellow with orange lining between each spike.

Crosspathing with path 2 adds two vents above the left and right side gears, as well as painting the feet purple.


Deadly Spikes now carries over up to two round instead of one, and each spike does 2 damage. In effect, spikes last up to 3 rounds or 140 seconds, whichever comes first. The spike carryover benefit has no effect on Apopalypse, but has effect on Boss Bloon Events. Deadly Spikes also has the benefits of Smart Spikes.

Targeting Priorities[]

Deadly Spikes defaults on Normal targeting priority, which dispenses the spikes onto nearby bloon track in a semi-sporadical behavior. Because it already has Smart Spikes, it will also receive Close, Far, and Smart.

  • Normal: Targets spike piles in a somewhat sporadical way, spreading spikes as evenly as possible within its range.
  • Close: Targets the closest region(s) of track within range.
  • Far: Targets the furthest region(s) of track within range.
  • Smart: Prioritizes the track with the Bloon the farthest through it, then targets the spot on that track closest to the exit.


Updated as of Version 32.0. Listed prices exclude external buffs, any sacrifices, and Monkey Knowledge.
Purchase Sell
Costs Easy Medium Hard Impoppable Easy Medium Hard Impoppable
Upgrade (X-X-4) $2,975 $3,500 $3,780 $4,200 -
Total (0-0-4) $5,480 $6,450 $6,960 $7,740 $3,836 $4,515 $4,872 $5,418
Crosspath (1-0-4) $6,160 $7,250 $7,825 $8,700 $4,312 $5,075 $5,478 $6,090
Crosspath (2-0-4) $6,670 $7,850 $8,475 $9,420 $4,669 $5,495 $5,933 $6,594
Crosspath (0-1-4) $5,990 $7,050 $7,610 $8,460 $4,193 $4,935 $5,327 $5,922
Crosspath (0-2-4) $6,670 $7,850 $8,475 $9,420 $4,669 $5,495 $5,933 $6,594

This upgrade's prices (or included crosspath's prices) are affected by the following MK: FirstLineOfDefenseIcon.png First Last Line of Defense, BetterSellDealsIcon.png Better Sell Deals



Deadly Spikes is a somewhat situational upgrade whose benefits rely primarily from long-term stalling, and it is prominent compared with Long Life Spikes. This upgrade enhances Spike Factory's stockpiling potential and it is recommended to be used for defensive purposes to maximize its efficiency. Spikes from this factory last in between rounds even longer but their time-based lifespan remains unchanged, meaning that Deadly Spikes eventually reaches its stockpile cap. In combination with the +1 damage bonus, the improved carry-over mechanic helps Deadly Spikes excel in the early-to-mid-game, and mainly when saving for Perma-Spike.

An improperly used Deadly Spikes is poor at simply tanking large amounts of bloons in a short period, especially compared to Spiked Balls which has an opposite purpose; the design of Deadly Spikes encourages stalling for a large stockpile. For example, it can tank leaking Camo Bloons reasonably well, but it will find difficulty beating the Camo Ceramics on Round 51 or the rushes of Camo Rainbows on Round 56 if not enough stalling is done. But, if stalling is done properly, it can easily tank a good chunk of camo bloons if granted external support.

When it comes to synergy for Deadly Spikes, stalling and external buffs are key. Stalling options such as Downdraft and cheap grouped bloon poppers such as Wall of Fire are best in combination with Deadly Spikes. Similarly to Long Life Spikes, Deadly Spikes appreciates external support such as Berserker Brew and Stronger Stimulant, which helps elevate its otherwise generally low pierce and attack speed in addition to gaining a substantial damage bonus.


  • Deadly Spikes is mostly a minor stat buff that empowers an existing Long Life Spikes. Long Life Spikes can achieve fairly similar power with Alch buffs such as Berserker Brew, though Deadly Spikes can be added on top for a further damage bonus.
  • Alone, a Deadly Spikes is not reliable at soloing Camo Bloon rounds, particularly Rounds 51 and 56. It requires more defense to counter stronger Camo waves, and tends to be weaker in that aspect compared to Spiked Balls.
  • Without buffs, on average, and against non-ceramics and non-fortified, a 0-2-4 Deadly Spikes have the same total damage potential as a 3-2-0 Spiked Balls. However, when both are paired with Berserker Brew, 0-2-4 Deadly Spikes damage potential becomes much stronger, or as strong as the 3-2-0 Spiked Balls, only losing against Ceramics. One other advantage with Deadly Spikes is that they don't need to replenish piles whenever a round starts.
  • Similar to Long Life Spikes, it is generally better to opt for a 0-2-4 Deadly Spikes instead of a 2-0-4 Deadly Spikes, because the spikes refresh faster and a 0-2-4 Deadly Spikes synergizes better with Alch buffs. While 2-0-4 can have a better stockpile in the long-run, 0-2-4 has the benefit of higher synergy.

Version History[]

Deadly Spikes has overall been buffed since it was first released, but only slightly.

  • Buff Deadly Spikes now attacks 4x as fast for the first 2.5s of a round.
[...] Along with this we made a couple small tweaks buffing what should be the 'strength areas' of a few of the more underperforming high tier Spike upgrades
~ Ninja Kiwi, referring to Deadly Spikes and Spiked Mines
  • Buff Deadly Spikes lasts for more rounds (2 → 3).
  • Change Description changed to reflect the buff.
    • Changed from "Extra deadly spikes can pop through 2 layers per spike." to "Extra deadly spikes can pop through 2 layers per spike and last another round."
    • This change was not directly documented in the Patch Notes, however the balance change was.
Like a few other towers before it, the attack speed crosspath for Spike Factory has outshined the others. We have reworked the lower Spike Factory tiers to distribute this power more evenly while keeping high tier factories at a similar level of power.
~ Ninja Kiwi, referring to base Spike Factory versus Path 2 upgrades
  • Change Affected by Spike Factory crosspath speed changes.
  • Change [Undocumented] Affected by Smart target priority changes from obtaining the Smart Spikes upgrade


Official artwork[]



  • This upgrade is the second upgrade in the Bloons TD series to use the word "Deadly", the first being "Deadly Precision".
  • The Deadly Spikes round lifespan buff in Version 21.0 also indirectly affects Perma-Spike.