From Dungeons of Dredmor Wiki
"Summons the cold Winds Of The North to bedevil your foes and chill their flesh from the bone. Does damage over time and decreases their ability to dodge and their resistance to cold."
Arctic Swirly is essentially an upgraded version of the Arctic Vortex spell from the Viking Wizardry skill tree. It is casted by the Monstrous Mask, it costs 9 (with a 0.22 reduction per Magic Power point) --does this even matter?-- and reduces the target's 1, 5 and 1. It also applies a damage over time of 3 per turn for 4 turns, which increases by 0.10 for every Magic Power point. The exact amount of magic power a Monstrous Mask has is currently unknown.