Spike Factory (BTD6)

"Automatically generates piles of Road Spikes on the nearby track. Excellent last line of defense."

- In-game Description

The Spike Factory is a Support-class tower that was released in the initial release of Bloons TD 6. The tower retains its name and role from the Bloons TD 4 and 5 Generation, with significant additions. It did not receive any teasers prior to release, but it was first shown when the game was available to select YouTubers several days before BTD6's official release date.

Spike Factory produces spike piles sporadically around its range onto nearby bloon track. Spike piles have a set amount of spikes, equivalent to pierce of each spike pile. By default, Spike Factory spike piles have 5 pierce, but upgrades such as Bigger Stacks increases their pierce. Each spike pile is produced every 1.75s and lasts for up to 50 seconds. Spikes disappear after ending a round, but spike piles can last longer by purchasing Long Reach and its later upgrades. Powerful upgrades include hard-shelled spiked balls, deadly mines that explode upon spike depletion, a wave of shredding spikes, and near-permanent spikes.

It costs $850 on Easy, $1,000 on Medium, $1,080 on Hard, and $1,200 on Impoppable.

Description
The Spike Factory is a white-colored machine with four "feet", the front two "feet" larger than its back two, and a spout on its "head". The front of the Spike Factory has an icon depicting a circle with three tacks inside. On the right side from the perspective of the player, its steam channel is located there.

In a similar manner to prior installments, the Spike Factory shoots out clumps of five spikes at a rate of one spike pile every 1.75 seconds. Compared to other towers that transitioned from Bloons TD 5 to Bloons TD 6, the Spike Factory is one of few that has both its original upgrade lines intact. Spikes by default last for 50 seconds or 1 round, whichever comes first. Spikes can last for more time or more rounds with most Path 3 upgrades.

Path 1 is primarily based upon making stronger spike piles. Bigger Stacks increases number of spikes per pile from 5 to 10 (or 50 to 90 with Perma-Spike). White Hot Spikes allows popping of any bloon type, including Frozen and Lead, increasing power of spikes further. Spiked Balls (returns from Spiked Ball Factory) replaces usual spikes with spiked balls, dealing even more damage to all bloon types while further increasing pierce, especially versus Ceramics and Fortified. The Spiked Mines upgrade adds powerful explosions into each spiked ball that activate upon depletion. The new Tier 5 upgrade surpassing the upgrade now creates even more powerful mines at a much slower rate, capable of wiping out crowds of stronger bloons with ease.

Path 2 focuses on aggressive production, starting with faster production with its first two upgrades, Faster Production and Even Faster Production, and then leading to MOAB SHREDR (returns from MOAB-SHREDR Spikes) for increased damage to MOAB-class, and its final upgrades Spike Storm and Carpet of Spikes increasing the Spike Factory's potential for widespread area damage. The Carpet of Spikes upgrade bases upon the old Spike Storm upgrade from BTD4 by making each spike storm automatic while dealing even more damage overall.

The new Path 3 is a more tactical one, providing a variety of utilities that improve spikes overall. This includes providing increased area of coverage to a targeting priority to spikes that last longer before timing out and even pass over to the next round. Long Reach increases the range of the Spike Factory and increases lifespan of spikes. Smart Spikes (formerly named Directed Spikes) adds target priorities to the Spike Factory, increasing its reliability on multi-lane maps, and adds a brief but quick boost of attack speed whenever a round begins. Long Life Spikes takes the long lifespan spike further by allowing spikes to carry over rounds and last even longer on the track. Deadly Spikes increases the round lifespan further and deals extra damage. Perma-Spike takes the spike longevity concept even further by manufacturing high-damage spikes with very long lifespan but at a much decreased production speed.

Spikes by default last for 1 round or 50 seconds, whichever comes first. These spikes will last even longer with Long Reach, Long Life Spikes, Deadly Spikes, and Perma-Spike upgrades. With Long Life Spikes, each spike pile will last for 2 rounds or 150 seconds, whichever comes first. Deadly Spikes increases the spike pile duration to 3 rounds or 150 seconds, whichever comes first. For Perma-Spike, each spike pile will last for 4 rounds or 300 seconds, whichever comes first.

Items for the Spike Factory are available in the Trophy Store. The "Spike Factory Pineapples" cosmetic changes the Spiked Balls, Spiked Mines, and Super Mines so that they resemble Exploding Pineapples.

Target Priorities
The base Spike Factory defaults to Normal, which sets it to produce spikes in a pseudo-random formation, it will always target the same set of spots, using the same placement sequence in a loop. It gains extra target priorities once the Smart Spikes upgrade is bought.


 * 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.

Alternate attacks have a different set of target priorities:
 * Spike Storm ability will target all areas of the track on screen, with the only exception when crosspathed with 0-4-2.
 * 0-4-2 Spike Storm (with Smart Spikes) ability will only target lanes that are currently being used in a particular round.

Spike Factories naturally can ignore Line of Sight due to their lobbing attack. Similar to Alchemist potions, most Spike Factory spikes cannot deal air damage mid-way through flight. Instead, these spikes leap over until they eventually reside to their intended spot. Spikes produced right above the Spike Factory, however, will register for collision until the spikes move linearly outwards.

Stockpiling
The nature of the Spike Factory is to produce stockpiles of spikes. This allows it to build up spikes over time and therefore improve its primarily cleanup role. Spikes do not last infinitely, however, meaning that spikes will begin to deplete as rounds progress and spikes expire automatically whenever rounds ends once round lifespan is reached. More durable spikes can withstand longer periods of time before they begin to deplete or last for a longer number of rounds. Giving spike piles with extra time lifespan and round lifespan are both accessible via most Path 3 upgrades.

Maximum stockpile potentials of main spike attacks are listed below, ignoring start-of-round benefits from Smart Spikes or any external benefits:

For Spike Storm abilities, these spike stockpiles are treated differently. More specifically, the number of spike piles on screen is irrelevant compared to the total spikes on screen due to the fact that determining the number of maximum spike piles is extraneous information. Rather, it is better off looking at the maximum damage potential, average damage potential, and ability's uptime. Average damage potential is increased by shorter bloon tracks and can be affected by ability uptime. Ideally, Spike Storm abilities deal the most damage on shorter maps, maps with single entries and single exits, and maps with intersecting lanes (e.g. Logs, End of the Road, Winter Park); Blons would be the theoretical best case scenario.

The spikes also last shorter than the ability cooldown, the only exception being with the Carpet of Spikes passive ability. Activated ability has 40s cooldown, and 15s passive cooldown for Carpet of Spike's passive ability.

The values given for average damage potential are tested on Medium (base bloon speed) and on Hedge, a map with an average potential for possible intersecting points, contains only one entry and exit, and is relatively long. Testing for blimp damage is done with a Round 100 BAD.

When excluding external buffs, the following are the stats for Spike Storm and Carpet of Spikes abilities:

For explosions from Spiked Mines and Super Mines:

...

Monkey Knowledge
This section displays Monkey Knowledge that has effects on Spike Factory and its changes when compared to one by default:
 * OneMoreSpikeIcon.png One More Spike: Spike Factory stacks get +1 spike.
 * Spike stacks have increased pierce from 5 to 6.
 * Bigger Stacks from 10 to 11.
 * Spiked Balls/Spiked Mines/Super Mines from 14 to 15.
 * and Perma-Spike from 50 (90) to 51 (91).
 * FirstLineOfDefenseIcon.png First Last Line of Defense: Purchased price of first Spike Factory each game is $150 less.
 * The first Spike Factory will cost $700 on Easy, $850 on Medium, $930 on Hard, and $1,050 on Impoppable.
 * MonkeyEducationIcon.png Monkey Education: All Monkeys XP earn rate increased by 8%.
 * VeryShreddyIcon.png Very Shreddy: MOAB-SHREDR spikes deal +1 extra damage to MOAB-Class Bloons.
 * Each spike deals 6 damage for a total of 36 damage per stack (because the Monkey Knowledge "One More Spike" must be unlocked first), originally deals 5 damage up to 25 damage per stack.
 * BetterSellDealsIcon.png Better Sell Deals: All Monkeys sell for 5% more.
 * Increases sell potency from 70% to 75%.
 * HiValueMinesIcon.png Hi-Value Mines: Spiked Mines cost reduced by 1500.
 * Cost reduced from $8,075, $9,500, $10,260, $11,400 to $6,575, $8,000, $8,760, $9,900 on each difficulty.
 * VeteranMonkeyTrainingIcon.png Veteran Monkey Training: All Monkeys reload time reduced by 3%.
 * GlobalAbilityCooldownsIcon.png Global Ability Cooldowns: All Ability cooldowns for all Monkeys reduced by 3%.

Sounds
Most Spike Factories lack a sound, except for explosions from Spiked Mines and above, and abilities from Spike Storm and Carpet of Spikes.


 * This section is incomplete due to the lack of a sound. You can help by expanding it.

When a Spike Factory is placed on screen:


 * [construction placement]
 * [construction placement]

When activating Spike Storm Ability or producing automatic spike storms:
 * [Spikes producing]

Videos
TBA

Trivia

 * The Spike Factory can have problems with extremely fast bloons such as freeplay DDT's in BTD6 (about Round 200+). If Bloons go fast enough it is possible for them to pass over the spikes but not register hitting them causing the bloons to take no damage.
 * This happens because in one frame the bloon is behind the spike pile, and in the next frame the bloon is in front of the spike pile. It essentially teleported over the spike pile.
 * In BTD6, the Spike Factory spikes in Apopalypse automatically disappeared once a round ends, which rendered the Spike Factory much less powerful due to disappearing at the wrong time. This has been fixed, changing the spikes to last between rounds, like in BTD5.
 * Strangely, the cogs of the 4-0-2 and 0-4-2 Spike Factories are the ones that rotate the fastest, despite Smart Spikes being bought just as a crosspath. Every other combination of upgrades involving Smart Spikes has its cogs rotating noticeably slower.