High damage spikes become almost permanent.
~ Upgrade description in BTD6.

Perma-Spike (sometimes referred to as Permaspike) is the final upgrade of Path 3 for the Spike Factory in BTD6. Although it produces spike piles at a significantly slower rate (from every 2.2s to every 6.0s, excluding Path 2 crosspaths), it produces much more powerful spike piles that pop up to 50 bloons per pile (70 bloons with Bigger Stacks) and deal 10 layers of damage per spike for a total of 500 damage per spike pile (700 with Bigger Stacks), making it extremely powerful for stockpiling spikes. Despite the name, but in accordance with the upgrade's description, the spikes are not actually permanent. The spikes last between rounds and have a longevity of 3 rounds each or 300 seconds, whichever comes first.

It costs $25,500 on Easy, $30,000 on Medium, $32,400 on Hard, and $36,000 on Impoppable.


  • Always purchase this upgrade on single-exit maps near the end of the track. Then, spikes won't be used up immediately, allowing spike stockpiling to slowly make the tower more and more valuable.
  • It is recommended to purchase the Path 2 Upgrades (Faster Production and Even Faster Production) over the Path 1 Upgrades (Bigger Stacks and White Hot Spikes) as Bigger Stacks only increases its pop count per spike from 500 to 700 versus the Path 2 upgrades which improve spike production speed by a total of +75%. By purchasing Even Faster Production, the Permaspike produces an equivalent of 875 spikes per 6.0s.
    • An Acidic Mixture Dip not within the range of any other tower should suffice to allow lead/DDT popping, and higher tiers provide extra popping power although not required.
    • If needed, a Monkey Intelligence Bureau will guarantee all spikes pop lead and can buff other towers in its radius.
  • Overclock works exceptionally well with Perma-Spike and more when paired with Stronger Stimulant. In fact, it is still slow enough not to consume Alchemist buffs faster than can be re-supplied.
  • In order to optimize the Perma-Spike + Overclock synergy on CHIMPS Mode, a 0-2-3 Spike Factory needs to be placed between two Monkey Commerce Villages prior to placement in order to maximize the speed boost duration from Overclock. This is because two stacked discounts from the two Monkey Commerce Villages allows the total cost of a 0-2-5 Permaspike to become just below the $40,000 cost threshold, thereby increasing Overclock duration from 30 seconds to 45 seconds.
  • Note that leaving the game and re-entering will no longer erase the spike piles as of Version 12.0. Interestingly, Long Life Spikes and Deadly Spikes spike piles can be erased.
  • Be cautious of using Snowstorm, as Perma-Spike without White Hot Spikes (or using an MIB) cannot affect frozen MOABs, allowing them to cross Perma-Spike undamaged, especially if using 'smart' targeting, where all spikes end up in one pile. Note that Acidic Mixture Dip cannot grant frozen-popping, despite granting lead-popping.
  • Due to the nature that occasional server reconnections may be caused by the extreme lag on the device, even if the spike piles can be saved, it is better off not using Perma-Spike for Co-Op Mode.


Main article: Perma-Spike/Strategies

The above page contains in-depth information on how to use Perma-Spike, and also includes a very useful list of towers that synergise with Perma-Spike.

In short, Perma-Spike is exceptionally powerful when very careful spending and stalling techniques are implemented, due to the nature of this tower.

Version HistoryEdit


Nerf Perma-Spike price increased ($22,000 → $25,000).

Nerf Perma-Spike now attacks 50% slower (3.0s --> 6.0s).


Buff Permaspike with Bigger Stacks now has larger stacks (60 --> 70; effectively now up to 700 damage per spike pile for Permaspike with Bigger Stacks)

  • Nerf Perma-Spike duration decreased from 350s-> 300s
  • Nerf Perma-Spike price increased from 25k to 30k
  • Nerf Perma Spike max rounds reduced from 4 -> 3
  • Buff Perma-Spike spike piles can now be saved (i.e. on any type of game save, including Co-Op saves)

Buff Perma-Spike now attacks 4x as fast for the first 2.5s of a round.

  • Change balloon Description changed from "Spikes become almost permanent." to "High damage spikes become almost permanent."
    • Undocumented in Patch Notes.




  • Contrary to popular belief, the Perma-Spike does not have a cap on the number of spikes, or a spike pile limit. The only limit is from the spikes decaying.
  • Between Version 2.0 and 11.2, a 0-2-5 can achieve a spike pile that can store around 65,000 pops worth of spikes if allowed to create a full stack.
  • The description of the upgrade reads "Spikes become almost permanent.". However, the spikes from Perma-Spike only last 3 rounds or 5 minutes, whichever is sooner.
  • Contrary to popular belief, x-0-5 Permaspike did not have the same attack speed as x-0-4 Deadly Spikes in v1.0 at the game's launch. The attack cooldown actually dropped from 2.2 seconds to 3.0 seconds, later to be nerfed to the current value of 6.0 seconds.
    • Interestingly enough, before Overclock became nerfed in Version 14.0, activating the Overclock ability onto a Perma-Spike would cause the Perma-Spike to attack at the same rate as before the pre-2.0 nerf, as the former +100% attack speed bonus balances out the halved attack speed nerf to Perma-Spike.
  • Although Permaspike was not specifically stated to be buffed, it got indirectly buffed by the Deadly Spikes round lifespan buff by +1 round.
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