Regularly sets a carpet of spikes over the whole track.
Carpet of Spikes is the final upgrade of Path 2 for the Spike Factory in BTD6. It allows the Spike Factory to automatically shoot out Spike Storms every 15 seconds. The automatic "Carpet of Spikes" spike piles will last for just over 20 seconds at minimum and will continually maintain its ever so deadly spike carpet. In addition, each spike deals +2 damage on top of the MOAB SHREDR upgrade, in effect dealing 7 damage to MOAB-class instead of 5.
It costs $34,000 on Easy, $40,000 on Medium, $43,200 on Hard, and $48,000 on Impoppable.
Carpet of Spikes is specifically designed for widespread area damage, and its main strength comes from regularly spreading high-damage spikes across the map to severely weaken MOAB-class bloons, especially strong singular bloons. Its main weakness comes from wasting damage on much weaker bloons, but pairing up a Carpet of Spikes with towers specifically designed to counter weaker bloons, especially for countering Super Ceramics. Provided it is supported by effective Super Ceramic counters, Carpet of Spikes is pretty decent overall as an option for high damage to high-HP blimps as well as general blimp damage. Although not the most efficient option compared to alternate options, it is still rather reliable overall.
The Carpet of Spikes automatic ability is affected by any speed buffs that would affect the activated ability. Be sure to increase the attack speed of this tower whenever possible.
It is often best to go for Path 1 instead of Path 3, as the Bigger Stacks upgrade literally doubles the total popping power of Carpet of Spikes. Not only that, but White Hot Spikes can also be bought to pop DDTs. This is generally more important than the benefits provided from Long Reach or Smart Spikes.
With that said, a 0-5-1 Carpet of Spikes will almost always have two-layers of spikes on the field. However, the early-round speed boost from a 0-5-2 can be difficult to manage and unreliable.
0-5-2 Carpet of Spikes perform significantly better on multi-lane maps that contain alternating lanes, with best examples being Muddy Puddles and Bloody Puddles, but this loses out on the White Hot Spikes upgrade for the cheap lead-popping. Add MIB to allow a 0-5-2 Carpet of Spikes to affect DDTs.
Although Carpet of Spikes deals 3 damage to all bloon types and 7 damage to MOAB-class, Carpet of Spikes is still far from the most cost-efficient MOAB-class damage source. It is still generally better off going for more Spike Storms, as using many more Spike Storms is usually more efficient against MOAB-class bloons than a single Carpet of Spikes for the total price.
However, Carpet of Spikes is much more reliable versus Super Ceramics compared to an equivalent number of Spike Storms.
Due to its expertise towards shredding MOAB-class bloons, pair a Carpet of Spikes with good anti-bloon popping power, such as The Bloon Solver, The Biggest One, or Prince of Darkness, so that the special spike carpets becomes less wasted on regular bloons.
The special "Carpet of Spikes" passive ability is affected by the cooldown reductions of Energizer, so do pair with it to produce much more frequent carpets.
Similarly to high-projectile towers like Tack Zone, Carpet of Spikes benefits hugely from buffs from Pat Fusty's Rallying Roar or from any bloon debuff towers like Super Brittle or Cripple MOAB. This is because each individual spike counts as a single hit, so a single spike pile counts for multiple hits, and therefore a spike pile's total damage can be highly amplified with bloon debuffs.
Like Spike Storm, Carpet of Spikes has a great synergy with Call To Arms and Homeland Defense, as it gains more than double the overall DPS compared to any other towers supported by these aforementioned towers.
The description used to be "Sets a carpet of spikes over the whole map, every round." but this has changed in Version 4.0 to match its new effect.
It formerly allowed the Spike Factory to automatically send a more powerful Spike Storm before every round starts. These spikes would last until the round ends.
This upgrade is similar to the Spike Storm upgrade in BTD4 and BTD4E.
This was not the case before the 4.0 update.
It is also equally as fast but lasts longer than in BTD4 and BTD4E.
Since the Spike Factory retains its regular Spike Storm ability as well, it essentially combines the BTD4 and BTD5 variants.
The Version 20.0 buff to Carpet of Spikes was listed as a bug fix rather than a balance change in the official Version 20.0 patch notes, but due to its significance it has made Carpet of Spikes considerably stronger overall.
On Logs CHIMPS, a 2-5-0 Carpet of Spikes can solo all of the camo bloons as of Version 20.0, leading to specific 3TC combos to be possible. Carpet of Spikes eventually completed its first 2TC combo in Version 21.0 with both the buffs to Prince of Darkness and Carpet of Spikes.
The Version 21.0 buff by increasing the automatic spike storm rate makes the Carpet of Spikes attack a little more similar to the BTD4 counterpart.