A nice little summon that reduces enemies Ice Resist by 30%. This is what made Ice Engineers a very popular for a long time. This was because you could stack the Ice resist of Frost Quacker and Mecha-Mode Frost Quacker for a total of 60% reduction in Ice Resist. With the April update they patched this and both effects no longer seem to stack sadly. It's still a nice summon to have, especially to help an Ice Witch/Adept with Ice Stacking. Recommended to get at least 6, but you can put extra points into it for extra duration for the debuff.
[Special Note 1: Through extensive testing, I've found that the duration of Frost Quackers debuff is dependant on the targets Ice Resist, despite being a skill that reduces Ice resist. So keep that in mind when choosing what level you want to level this skill to. See the Testing Zone for information on my results.]
[Special Note 2: An additional choice is to just get level 1 as a pre-requisite. The reason for this is to favor Gatling Quackum as your 3rd tower to increase your total damage instead of Frost Quacker. I don't particularily favor this as any raid team should have an ice stacker of some kind and the extra Ice Resist reduction is always helpful. Another reason I dislike not leveling Frost Quacker to level Gatling is due to Gatlings general inaccuracy and inconsistent damage. Even if I had Gatling, I would probably not summon it in favor of just summoning Cannon and Chainsaw quickly to deal more damage myself.]