The Fire Extinguishers
Although both Jack and Danny see the fire extinguishers move, and Danny is particularly frightened of them, they don't prove menacing. In fact, they are what they seem, rather puny creatures, unfit for their raison d'être, putting out fires. They are certainly no match for the boiler explosion that proves fatal for the hotel. They are a further symbol of the hotel's perversity, where things which are supposed to protect (like fathers, for example) are twisted to do the opposite.