Colly still gets terribly confused about holy water, as he's never seen water with holes in it before, and he's a bit scared that his owners will give him some in his bowl one day, as surely it would leak through the holes in itself and somehow disappear (quite how and where it would escape too he has never yet worked out. Possibly into one of those rather scary sounding black holes which he sometimes hears of on the TV or something).
He has managed to pacify himself in recent times after coming to the rather hopeful conclusion that they must in fact get it out of a hole (but not a black hole), a theory which is backed up in Colly's mind as he sometimes drinks water from the hole in the toilet.