Crippled MOABs are immobilized for longer and take extra damage from all other attacks.
~ BTD6 description
Cripple MOAB is the fifth upgrade of Path 1 for the Sniper Monkey in Bloons TD 6. It allows the Sniper Monkey to temporarily stun and cripple MOAB-class Bloons (7.0s for MOABs, 6.0s for BFBs, 3.0s for ZOMGs, 4.0s for DDTs, and 0.75s for BADs), causing them to become vulnerable to +5 damage for the stun duration (or debuff duration for BADs). It deals 80 damage per hit instead of 30, plus +15 to Ceramics. With Shrapnel Shot, each shrapnel piece deals 12 damage instead of 6 from Maim MOAB, and can apply both stun and debuff.
Cripple MOAB specializes at crippling single-target blimps, especially for ZOMGs and BADs. Its main benefit is not from its increased damage, but from helping other towers apply extra damage to blimps affected by the Cripple MOAB. In combination with towers with high projectile count and high attack speed, affected blimps will become destroyed a lot more quickly. Its infinite range is a major benefit to its overall performance.
Cripple MOAB by itself will not deal much damage. It will reach its optimum when paired with fast towers such as Super Monkeys, or towers that shoot multiple projectiles per shot such as Overdrive, since they will help quickly damage MOAB-class bloons crippled by Cripple MOAB.
Similar strategies that Super Brittle would require to optimize its strengths can also be applied to Cripple MOAB, although Cripple MOAB has the advantage to attack at any range.
Unlike Maim MOAB, it's far more important to set Cripple MOAB to Strong, unless it's for stunning blimps closer to the exit. The combined stun and debuff effects last a considerably long time on affected blimps, so there should be less worry for blimps to start moving again.
As of Version 20.0, the debuff effect of Cripple MOAB for all MOAB-class Bloons below a BAD lasts longer than the base tower attack speed. Using the 5-0-2 crosspath allows almost full uptime at crippling BADs, while any crosspath will always cripple the same blimps as long as it hits them consecutively each shot.
Normally, the optimal crosspath for Cripple MOAB should be based on the defense's needs. Because it can permanently stun and debuff any blimp below BAD regardless of crosspaths, the 5-2-0 Cripple MOAB is a good choice for combating rounds before Round 100, as it can apply those effects to multiple blimps per shot, naturally detect DDTs, and can deal more damage via its improved shrapnel. The 5-0-2 Cripple MOAB is still superior at applying a near-permanent debuff to BADs, as it attacks fast enough to apply almost full crippling uptime.
However, a 5-x-0 Cripple MOAB can shoot every 0.811s if adding both Jungle Drums and Overclock, which means the uptime versus BADs can actually be almost on level with a raw 5-0-2 Cripple MOAB's stun uptime. That is equivalent to just over 92% uptime compared to the 96% uptime from a raw 5-0-2 Cripple MOAB.
Remember that Cripple MOAB and Super Brittle vulnerabilities can stack with each other.
Cripple MOAB's main role was to inflict vulnerability for single-target MOAB-class. However, initially dealt very little damage to the blimps themselves, and it initially did little effect to BADs due to how short they had applied debuff for. Cripple MOAB had been buffed in many updates, with extra damage, lower cost, extra stun time, and 5-2-0 interactions improving its performance in many different ways.
Cripple MOAB, like many other Sniper Monkey upgrades, had received crosspathing changes aimed to discourage exclusively Path 3 crosspathing. For this upgrade, 5-2-0 Cripple MOAB now deals more shrapnel damage and can stun and debuff blimps, making this crosspath viable against grouped blimps. The 5-0-2 crosspath remains superior versus BADs, however, but even this crosspath is now much stronger than when the Cripple MOAB was first released.
5-2-0 Cripple increases Shrapnel Shot fragment damage (1 → 5)
5-2-0 Cripple increases Shrapnel Shot fragment damage (5 → 12)
This tower felt like it's [sic] strength too heavily required the xx2 upgrade, and that this harmed crosspath choices. So we increased the base attack rate while nerfing the increase from these upgrades. This is a slight overall buff
~ Ninja Kiwi, referring mostly to base Sniper attack speed buff
Affected by base Sniper attack speed buff
5xx Cripple MOAB duration rates for stun/debuff increased
M.O.A.B.: 6 → 7
B.F.B.: 3 → 6
Z.O.M.G.: 1.5 → 3
D.D.T.: 1.5 → 4
B.A.D.: 0.25 → 0.75
To retain value in more Lead-heavy situations including against DDTs, this upgrade that has always allowed Lead popping to main attack will now also grant this to the Shrapnel from any shrapnel shot snipers mixing in this upgrade
~ Ninja Kiwi, referring to 1-2-0 Sniper's shrapnel
Affected by 1-2-0 Sniper buff.
Trading off rate of fire for shrapnel crosspath doesn't work well for Maim MOAB as it's all about being a stall tower, so instead of focusing on a damage increase here the shrapnel will now apply the benefits of the sniper's stun & debuff to turn this crosspath choice into a question of preference in grouping vs single target. [...]
~ Ninja Kiwi, referring to Maim MOAB and Cripple MOAB with Shrapnel Shot
5-2-0 Cripple MOAB shrapnel fragments now also benefit from stun and debuff.
Small improvements for underloved sniper upgrades with respective path specialties intact. [...]
~ Ninja Kiwi referring to buffing the "weaker" Sniper upgrades
Damage increased from 60 to 80.
Cripple MOAB's price currently limits it mainly to freeplay and so has been reduced.
~ Ninja Kiwi
Cripple MOAB price reduced from $40,000 -> $34,000
BTD6 Cripple MOAB
B.A.D. affected the damage vulnerability from Cripple MOAB (Note the cross marks).
Since Version 11.0, this upgrade applies an "X" mark on a B.A.D. for the debuff duration to indicate the debuff effect that other towers can utilize. The "X" mark stays longer with the Version 20.0 buff.
The Cripple MOAB in BTD6 visually resembles the older Cripple MOAB upgrade from BTD5, except the monkey now wears full black clothing underneath the bush disguise, and its rifle is covered in green tape and comes with a visible infrared light scope (official artwork only).
The upgrade icon for Cripple MOAB features a heavily damaged BFB propeller. This can be seen as a reference to the BTD5 Cripple MOAB's artwork.