There's something in this human's house. Tom Riddle knows it.
He doesn't really care about the humans much. They just live in their safe little town while he and all the other big bad Folk have the wilds and the hills. They don't bother the humans in this town, because these ones are clever, and have lived there long enough to know the Folkish ways. They fill their pockets with salt and iron and watch their babies well. So there is no point in paying them much mind, because little entertainment will come from it. They may be occassionally tempted into deals or drawn off the path to paint redcap clothing, but they know better than to do anything too interesting. They know better than to perform the kind of full blown self extinction that Tom Riddle is interested in watching.
But this one…. This one Tom has suddenly become very interested in.
This one's name is Harry Potter, he learns, listening in on human conversations from the tree line. He can do a lot of things with just a name, but he doesn't want to do any of them, and besides, this one wasn't given willingly by the owner. But he learns it, and other things, forming a list of all the things he knows about his precious new problem.
1: Harry Potter dwells a little away from everyone else, but not far enough away to be dangerously alone in the woods.
2: Harry Potter lives alone.
3: Harry Potter has big green eyes the colour of pixie blood and hair the black of grass on moonless nights. He has iron earrings and all the right kinds of branches in a wreath on his door to keep creatures like Tom out.
4: And this one is very important, Harry Potter smells funny.
5: This one is even more important, because Harry Potter smells like a corpse.
Tom cannot get close enough. He cannot get in his house or through his window, where there are the proper charms to keep him out, salt and all those branches. But he follows the little sprites to the bowl of milk on the doorstep, the offering left to the littlest, most harmless Fae that no one bothers to ward away. He smells the stiffening flesh from the crack beneath the door.
It's not a human. It's too much acid, too much field of flowers for the salty, heavy iron set of human blood. This smell is ever flowing, ever growing, getting stronger by the day. This is a scent that never dies down, until the body is consumed by flowers or turns to diamond dust or whatever other things unhuman things do when they die. Cloth can't hide this smell. And neither can a door, and Harry Potter can't wash it away when he reeks of it beyond what soap and water can remove.
It's a fairy.
There's a fairy corpse in there.
Now how did it get there?
Tom Riddle feels delighted.