I was just thinking "Hmmm, there was that manga, wonder what happened to it?" and bam! There it was. Well done.
Meanwhile, from the moment he said "from the waist down" I knew just what fearsome monster had appeared.
When they said winter monster invading homes at first I thought it was Santa but then he said he lost the lower half of his body then I knew it was a kotatsu
I want to try a kotatsu someday. Like, when it's seasonally appropriate. I tried it once, but I live somewhere where winters are a cool 60 degrees at worst, so it didn't really do much for me