Crosspathing/Monkey Sub

In Bloons TD 6, it is important to choose the best crosspathing for a specific tower in order to receive the best benefits out of that tower type. Towers have special roles to play for each stage of the game. The Monkey Sub in its core is a low-cost water-based tower packed with high value.

Introduction
Monkey Subs are one of the most versatile towers in the entire game across the early-game, mid-game and late-game. Its early-game is pretty strong, with its base tower acting as a powerful source of homing, second to Dart Monkey thanks to the Dart Monkey's cheap early-game upgrades. Nonetheless, the Monkey Sub features a significant amount of support-oriented and damage-oriented roles that alternatives tend to become shadowed by. Its weakness is mostly about the need to be placed in water, but its other noteworthy weakness is its mutually exclusive lead-popping and homing for the mid-to-late-game.

Tier 2 and below



 * 0-0-0: Valuable with its homing power and decent attack speed. It is necessary on CHIMPS when playing on Flooded Valley or Bloody Puddles.
 * 1-0-0: Adds more range to make it more compatible with maps that require the extra range. 1-0-0 is the only affordable Sub crosspath on the start of CHIMPS aside from the base tower.
 * 0-1-0: Occasionally, the 5 pierce per dart instead of double attack speed from 0-0-1 is better, for the same price as each other. 0-1-0 tends to work better for handling grouped early-game waves rather than counter spaced ones.
 * 0-0-1: Often upgraded from an existing 0-0-0 Sub. While more expensive than two 0-0-0 Subs, it can produce lots more darts within a short range, often overproducing darts against spaced bloons. This behavior of the 0-0-1 Sub provides much of its value at handling the early-game.
 * 1-1-0: TBA
 * 1-0-1: Basically a Twin Guns with more range. When the little bit of extra range is needed for a 0-0-1 Twin Guns, or when saving up for 2-0-1 Advanced Intel, this upgrade can be used to barely push the defense to safety.
 * 0-1-1: As a combination of Barbed Darts and Twin Guns, it is a relatively fast-attacking Sub with moderate pierce darts with fair accuracy.
 * 2-0-0: The non-crosspathed Advanced Intel is useful for getting an early-game head start for the Sub to make the most of creating as many dart attacks as possible. Works best at long range when compared to other lower-tier crosspaths.
 * 0-2-0: The cheapest option for a Sub to pop Leads is to get Heat-Tipped Darts.
 * 0-0-2: An effective early-game option for specifically popping early fast bloons and grouped bloons within short range, thanks to its airburst attack. It can hit the same bloon more than once and comes with a decent amount of pierce.
 * 2-1-0: TBA
 * 2-2-0: Combining Advanced Intel with Heat-Tipped Darts, it has high-range lead-popping power. Not nearly as reliable as Snipers, but it does work on water-heavy maps.
 * 2-0-1: Long-ranged 2-0-0 Sub packed with twice the normal dart value. More cost-effective than another 2-0-0 Sub. Can chase faster bloons better but still finds it hard to beat early grouped bloons.
 * 1-2-0: TBA
 * 0-2-1: TBA
 * 1-0-2: Basically an Airburst Dart Sub with more range, perfect for transitioning into 2-0-2 while gaining a sizeable range increase.
 * 2-0-2: Powerful early-game tower that combines open range with airbursts, allowing it to clean up fast early-game bloons and deal decently with early game grouped bloons from any reasonable distance. Best used on maps where there is little to no Line of Sight, such as Muddy Puddles or even Bloody Puddles. May have trouble on split simultaneous multi-lane maps such as Quad.
 * 0-1-2: Offers a high amount of pierce within a close range, combining Airburst with extra internal pierce. The +3 pierce does apply with each individual airburst dart, for higher overall popping power. Works well against groups of bloons within a short range.
 * 0-2-2: Offers reliable early-game lead-popping within close range, combining Airburst with internal lead-popping. Mostly helpful in Flooded Valley.

Submerge and Support

 * 3-0-0: Crosspathing doesn't truly matter for this tower as its main strength comes from being submerge into the water. Crosspathing with Path 2 is useless unless it's for unsubmerging it, while Path 3 improves rate of submerging.
 * 3-1-0: Useless for Submerge and Support as it is supposed to be support-oriented, and Barbed Darts does nothing to the submerge crosspath for this upgrade.
 * 3-2-0: Buying the "Angry Sub" may look cool, but it isn't very useful. The option to unsubmerge where there are Leads that need popping can come in handy, but the submerge attack is not at all affected by the Heat-Tipped Darts upgrade.
 * 3-0-1: Can decamo slightly faster, slightly more useful for decamoing faster bloons.
 * 3-0-2: Decamos bloons even faster, for even more reliability. At this point, Reactor would be far more useful, but if the pure decamo is needed and not the damage, then 3-0-2 is a fine choice.

Bloontonium Reactor

 * 4-0-0: Gains a very fast decamo rate and deals damage. Crosspathing does make use of its offensive attacks more than it does for decamo.
 * 4-1-0: Gains more pierce. Opting for 4-2-0 adds the maximum pierce bonus.
 * 4-2-0: Normally not the best crosspath outside of Race Events, where pierce usually matters more than attack speed. May be useful against dense rounds. It gaining the ability to pop Lead Bloons is usually pointless outside of races as other cheap lead popping like Full Metal Jacket or Buccaneer's Hot Shot can accompany a 4-0-2 sub instead.
 * 4-0-1: Unlike 3-0-1, 4-0-1 doesn't have a significant increase in decamo, as Reactors decamo pretty quickly anyway. Rather, 4-0-1 slightly increases the damage rate of its radioactive zone.
 * 4-0-2: Generally the best crosspath, as being able to damage bloons faster is usually preferred over pierce, as the reactor's pierce is already rather high.

Energizer

 * 5-0-0: Its purpose is mostly attributed to a support role, so crosspathing usually does not matter. However, a crosspath is likely to be inherited from a previously crosspathed reactor.
 * 5-1-0: See 5-2-0
 * 5-2-0: Do not pay for this crosspath at all costs. Its extra 50 pierce is insignificant (compared to its already very high 1000 default pierce), and its Extra Damage to Leads bonus is worthless by the time you can afford an Energizer. It is worthless at bettering the DPS of the Energizer's radiation attacks.
 * 5-0-1: See 5-0-2
 * 5-0-2: The most optimal Energizer crosspath, as the it allows its 3-damage radiation damage to occur over 25% more often, and thus significantly increase the radiation DPS.

Ballistic Missile

 * 0-3-0: There is no reason not to crosspath a Ballistic Missile unless going for First Strike, as its ballistic missile attacks provide the majority of its high-pierce, high-damage potential. Crosspaths are expensive for a Ballistic Missile, but they can be worth it for beating singular targets. Path 1 crosspath is oriented for gaining opportunity to let it attack further, while Path 3 crosspath is the superior short-ranged option.
 * 1-3-0: Not very useful, as ballistic already has a decent amount of range.
 * 2-3-0: Increases ballistic range to attack into any tower's range, not very useful in most situations unless ballistic can only barely hit the track. All of a 2-3-0 Ballistic's attacks can detect camo provided that at least one tower with camo detection is on screen and their range(s) overlaps bloon track.
 * 0-3-1: Gains extra attack speed for both its darts and missiles. Using 0-3-2 adds the greatest DPS value on top of the bonus attack speed benefits.
 * 0-3-2: Best crosspath, adds heat-tipped airburst darts for extra DPS. Combined with the already decent range and pierce of the Ballistic Sub, the additional airburst darts further increase potency against MOAB-class bloons.

First Strike Capability

 * 0-4-0: Go straight for 0-4-0 if using the First Strike Capability ability. Otherwise use a crosspath depending on the Ballistic Missile attack's purpose. Its main ballistic missile attack is no different from the previous upgrade.
 * 1-4-0: See 2-4-0
 * 2-4-0: Advanced Intel is not required for the ability to target outside its immediate range. Otherwise treat it as a 2-3-0 Ballistic Missile.
 * 0-4-1: As with 0-3-1, improves attack speed of both darts and missiles.
 * 0-4-2: As with 0-3-2, adds a helpful short-ranged airburst attack.

Pre-Emptive Strike

 * 0-5-0: The main power of Pre-Emptive Strike comes from the passive ability that creates missiles that deal an instant 750 damage to incoming MOAB-class bloons, each hit removing up to one blimp layer if the incoming target blimp's health is low enough. Pre-Emptive Strike attacks faster and deals more damage with its ballistic missile attack, but the majority of its damage does come from its passive ability, which isn't affected by crosspathing. Nonetheless, it's a good idea to crosspath Pre-Emptive.
 * 1-5-0: Doesn't do much in itself because it already comes with decent range, and extra attack speed would be more favorable.
 * 2-5-0: All its missiles can hit bloons more often by increasing range, provided there's enough range coverage across the whole map. Its activated ability and pre-emptive missile attacks are not affected by this crosspath or any crosspath, however.
 * 0-5-1: As with 0-3-1, improves attack speed of both darts and missiles. Note that missiles attack much faster, so this small Twin Guns attack speed boost amplifies more here.
 * 0-5-2: Adds helpful short-ranged airburst dart attacks.

Triple Guns

 * 0-0-3: Triple Guns is simply a faster Airburst Darts Sub. Generally an okay tower, but crosspathing is needed to make it actually viable.
 * 1-0-3: Only used as a stepping stone for 2-0-3. More range is desirable, but in itself is not much effect.
 * 2-0-3: The much more versatile crosspath, and is often preferred to other crosspaths. It has virtually unlimited range, as long as other towers are on the screen.
 * 0-1-3: The pierce is okay-ish for certain situations, but general outclassed by the upper crosspath.
 * 0-2-3: Popping Frozen and Lead is helpful for both popping Leads and synergizing with Ice Monkeys, but generally is situational.

Armor Piercing Darts

 * 0-0-4: Armor Piercing Darts adds greater MOAB-class damage on top of a higher on-hit damage with its main darts. As with most Sub upgrades, crosspathing is key for optimizing the power of Armor Piercing Darts.
 * 1-0-4: Extra base range is helpful. However, this crosspath is mostly used as a stepping stone to 2-0-4.
 * 2-0-4: Generally the best crosspath due to optimizing its high damage potential across a wide range, especially versus MOABs.
 * 0-1-4: Armor Piercing Darts already comes with extra pierce, but if more pierce is required within short range, this crosspath is an option. Still not as versatile compared to 2-0-4.
 * 0-2-4: Pops Lead, and can be used as anti-DDT popping power or just popping leads. The 0-2-4 Sub's role at anti-DDT power is redundant for Sub-only CHIMPS, given that Pre-Emptive + Sub Commander can already neutralize normal DDTs anyway and BADs can have its DDT offspring bypassed with a First Strike.

Sub Commander

 * 0-0-5: Sub Commander gives itself and all Subs within range with double damage and +4 pierce for almost all attacks except First Strike Capability ability missiles. The non-crosspathed Sub Commander is mainly for giving the buff itself. Unless attempting a difficult custom 2MPC challenge with a single Sub other than itself, crosspath the Sub for maximum influence range and more DPS.
 * 1-0-5: Increases influence range to allow more Subs within range to gain the Sub Commander buff. Even without Sub Admiral MK, the 1-0-5 crosspath is useful, especially because 2-0-5 is even better.
 * 2-0-5: Not only does it increase the Sub Commander's influence range because of 1-0-5 crosspath's range increase, this allows Sub Commander to add significantly more DPS potential for the defense. For a remarkably low cost in comparison, it is very worth the purchase.
 * 0-1-5: Gives the Sub Commander's darts with more pierce, but does nothing for its buff to nearby Subs. Normally useless, unless it is the only tower on screen.
 * 0-2-5: Heat-Tipped Darts allows the Sub Commander itself to pop Frozen and Leads. Normally poor crosspath except in the very rare case where an APC (All Pops CHIMPS) with Sub Commander is to be attempted.

Strategy
TBA