The third episode of Dusk Maiden of Amnesia (Tasogare Otome x Amnesia) has a fascinating hook: perception.
it is critical to the nature of Yuuko - she only exists because others can see her
In the context of the episode it arrives when Kirie challenges Teiichi's vision of Yuuko as a busty, alabaster skinned school-girl and instead claims she is "dripping with hatred" with filthy, cracked skin. From then on Teiichi can only see this ghoulish visage of Yuuko until he forcibly excises it from his mind. It's claimed in an earlier episode that Yuuko only exists in the form of the beholder, so if someone believes her to be a wandering spirit then that's what they'll see her as.
Boogiepop Phantom is a series which immediately makes one wonder whether their television is functioning correctly. Shortly after the melancholy opening it adds the speakers to that list. By the end of the first episode it adds the viewer's brain. It is a reverie of madness, murder, altered states and narrative intrigue: each episode teasing an explanation but rarely delivering in full, each appearance of the titular Boogiepop - or is it the Manticore? - promising a new thread to tie in with the myriad others. Existing in a microcosm of light novels, manga and a live-action movie as well as sharing idiosyncrasies and the brutally obtuse style of its spiritual predecessor, Serial Experiments Lain, the question the series' lineage poses is whether it can stand by itself or whether it relies too much on its forebears and source material to support itself.
some of the darkest aspects of humanity are explored with obsession, madness and memories playing a key role
A month before the opening of the series, a pillar of light erupts in a nameless cityscape, dragging it into darkness. Those who witness the light began to change, much like the city itself, now with a permanent aurora in the sky and a magnetic field that makes compasses useless and corrodes metal at a frightening rate. Those who changed exhibit strange powers: the ability to see and consume insects clutching peoples' chests, the power to separate composite objects like coffee or humans even the capability to show people scenes of their pasts. All the while they are stalked by the urban legend Boogiepop, supposedly the personification of death, who appears without warning to rid the world of the deviations that have sprung up. Clandestine talk of impossibly powerful corporations and unnatural evolution ensure that understanding the circumstances behind all of the strange occurrences will not be straightforward.
