Spike Factory (BTDB2)

TBA

"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 Battles 2.

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 $800 to place.

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 vent 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. Spikes by default last for 50 seconds. Unlike BTD6, spikes will not disappear at the end of the round, regardless of upgrades. Spikes can last for more time 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 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 Tier 5 upgrade upgrade 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 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.

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. Long Reach increases the range of the Spike Factory and increases lifespan of spikes. Smart 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 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 50 seconds. 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 150 seconds. Deadly Spikes increases the spike pile duration to 150 (???) seconds. For Perma-Spike, each spike pile will last for 300 seconds (???).

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 time passes and spikes expire automaticall once their lifespan is reached. More durable spikes can withstand longer periods of time before they begin to deplete. Giving spike piles with extra time lifespan is accessible via most Path 3 upgrades.

Summary
TBA

Spike Factory is a stockpiling expert. The more Spike Factory is left around to pile up more spikes, the stronger it becomes. At maximum stockpiling, it becomes really strong for its price. Part of its design is mostly to secure exits, though it can be used to simply accumulate huge amount of damage when bloons run the spikes over.

Spike Factory dispenses spikes every few seconds, probably every 1.75s. Each spike pile caps at around 50 seconds (or at least predicted to do so), or 100 seconds for Long Reach and longer for other upgrades along Path 3. As mentioned before, Spike Factory's stockpile potential makes it optimal for securing exits and tanking spaced bloons.

More info here...

Further Strategies

 * Strategies
 * General Strategy
 * Optimization Strategy
 * Countermeasures Strategy

Trivia

 * On the team screen, which can be shown on the main menu of the game, if the player has Spike Factory in their last game, Spike Factory regularly raises itself in and out, as if it is sentient. The animation is shared on this post on r/battles2.