Bloons take huge damage while frozen including MOAB-class Bloons.
~ BTD 6 Description
Super Brittle is the fifth and final upgrade of Path 1 for the Ice Monkey in Bloons TD 6. It allows the tower to pop 5 layers of bloon, including M.O.A.B. Class Bloons, White Bloons, and Zebra Bloons. It also attacks about 11% faster. Any Bloons, including M.O.A.B. Class Bloons, that are damaged by Super Brittle will take +4 damage from each attack that hits it. M.O.A.B. Class Bloons are not frozen in place, but still take additional damage. Any MOAB-class bloons that become affected by Super Brittle will become vulnerable to bonus damage for up to 3 seconds, after which Super Brittle will be able to reapply its special vulnerability effect. It costs $25,500 on Easy, $30,000 on Medium, $32,400 on Hard, and $36,000 on Impoppable.
It is recommended to purchase a 5-2-0 Ice Monkey rather than a 5-0-2 as the monkey's fire rate is still slow. Also, Re-Freeze is almost useless against M.O.A.B. Class Bloons because the 3-second vulnerability effect cannot be reapplied until the duration is over, even with the Re-Freeze upgrade.
As of Version 7.0, this upgrade has the smallest range out of any Tier-5 tower, excluding all towers whose "range" is represented for inclusion purposes (of which are Sniper Monkey, Heli Pilot, Monkey Ace, and Mortar Monkey).
Absolute Zero used to also have the smallest range, but since Version 7.0 Absolute Zero now has twice the range of a normal Ice Monkey.