The dead aren't buried in wooden boxes anymore. They may have one to serve as their final bed, but in most places, the dead are buried in cement. If their families can afford it, the cement is itself poured into the dirt, protecting the casket and corpse from the worms while also preventing the only beneficial function of a corpse from being completed. In other places, the bodies are slid into concrete walls with plaques at the foot of the compartments, telling passers by who is piled on top of who. That's if they're not burned and put in steel boxes or fancy jars.
He used to prowl around cemeteries before they started with the concrete. Now he has to make do with morgues. Nobody notices him when he enters the building. Later on, after the bodies go missing, the reviewed security footage won't reveal him. If he goes during the day the staff won't see him, even as he walks right in front of their faces. It's a trick he learned so long ago that he can't remember where exactly he picked it up.
When he gets to the bodies, he knows immediately which one it is that's caused the itching in his head.
He goes to it. He touches it.
And then it's gone.
No flash, no smoke, just absence.
He doesn't know what happens to the bodies. What he does know is that he feels. . . content after it's gone. There's a fullness in his belly and his heart that will last for weeks after before wearing off.
He slips out of the door, past the oblivious security guard, and back onto the street, ignored by all until the itch comes back.