The slime slid down from the roof and landed in a pile in front of their doorstep. They might have stood there horrified, if they had had enough sense. As it was, they were too confused about what the mass could be to be horrified yet. They wondered if there was something on the house that could leave behind that sort of residue.
They stepped outside, in their slippers, because they hadn’t been bothered to put on actual shoes. Not at this time of evening, when they were winding down from the day. They walked over to whatever it was and looked at it. It could have been a glob of anything, as far as they were concerned. There was no colour.
Making a face, they decided wisely not to touch it. They would grab the hose and spray it away. It was like a drop of gelatin or something and whatever it was they just wanted to clean it up. They went back inside in order to get on some proper shoes.
Coming out to hook up the hose, they found instead that they couldn’t do anything with it because it was completely gone at that point. The slime had disappeared. They stared, wondering where it could have gone, decided that it had slipped down to the sewer drain somehow and that it was no longer their problem. They went back inside.