Icicle Impale

"Shoots huge icicle spikes that do huge damage to MOAB-Class Bloons and freezes them."

- In-game description

 is the final upgrade of Path 3 for the Ice Monkey in BTD6. The Ice Monkey's snowballs can now target and damage MOAB-class bloons, dealing 50 damage to each and freezing them. Frozen MOABs and BFBs move at the base speed of a ZOMG, and frozen ZOMGs are slowed by 50%; BADs can be frozen but will not be slowed down. This unique slowdown versus non-ZOMG blimps becomes far more apparent on higher rounds.

Icicle Impale also allows the snowballs to directly pop White and Zebra Bloons. Additionally, the Ice Monkey now attacks 33% faster (or 0.75x attack cooldown reduction), increasing its default firing rate from per 1.0s to per 0.75s. Crosspathing with Permafrost also applies a permanent 25% slowdown to the outer layer of any affected MOAB-class bloons.

It costs $25,500 on Easy, $30,000 on Medium, $32,400 on Hard, and $36,000 on Impoppable.

Summary
Icicle Impale holds a unique place as a tower that solos DDTs and does very good damage to blimps in general. It also clumps up bloons, which may be useful to help certain towers fully utilize their pierce.

It can sometimes be a bit costly to afford for certain strategies due to its high price tag of $32k (at least on Hard Difficulty), but that depends on the strategy being used.

Tips

 * Since it can slow MOAB-class bloons down to a halt, it can serve very well against rounds such as Round 85, 90, 97, and 98 (plus Rounds 90, 93, 95, and 99 if given camo detection).
 * When given camo detection, placed in a good close or straight-line spot, and near a Monkey Intelligence Bureau or influenced by a lead-popping grant (Cold Snap upgrade, Acidic Mixture Dip, or Gwendolin with Heat It Up effect), it makes a good counter to DDTs.
 * It is worth a note that crosspathing Icicle Impale with Permafrost allows it to permanently apply a 25% slowdown to all affected MOAB-class bloons. However, since Icicle Impale would likely be fast enough to slow them down to a halt anyway, it's usually better off going for a 0-2-5 Icicle Impale. That being said, 2-0-5 allows direct popping of DDTs and does not require Radar Scanner due to that crosspath's innate camo detection.
 * MOAB-class Bloons that are slowed by the attacks count as frozen, so they become immune to sharp projectiles. Plan ahead and invest in towers and upgrades that can pop frozen Bloons.

Trivia

 * Prior to version 2.0, even if Icicle Impale did not have Metal Freeze, it could still freeze and damage DDTs with Camo Bloon detection.
 * As of version 2.0, it could still slow down DDTs, but it required Metal Freeze, Acidic Mixture Dip, or a Monkey Intelligence Bureau to deal actual damage to them.
 * As of version 25.0, it cannot damage or slow down DDTs without Metal Freeze or external support.
 * On certain Daily Challenges that specifically have decreased MOAB-class bloon speed, Icicle Impale can actually speed up MOAB-class bloons (except ZOMG, which will move at 50% speed, and BADs, which can't be slowed at all), due to the frozen status applying a set speed to such bloon types.
 * The upgrade icon for Icicle Impale is a MOAB impaled by a large icicle spike.
 * Despite what the patch notes mentioned regarding Cryo Cannon pierce not being affected by the change, Cryo Cannon and its subsequent upgrades actually received a pierce buff from 20 to 30. This also affects the Icicle Impale upgrade.