Notes:

Source is from pixiv.
A quick search on Hasshaku-sama lead me to Danbooru (NSFW) which has this to say on her :
" hasshaku-sama
八尺様
八尺様 (Hasshaku-sama, lit. Ms. Eight-feet-tall)
Titular monster of a 2008 fictional ghost story that was posted in "Let's gather up seriously, deadly scary stories, shall we? (死ぬ程洒落にならない怖い話を集めてみない?)" thread/topic of 2ch's Occult Board. This is regarded as one of the best stories in the thread.

Essentially a female Slenderman, she stalks and kills her young targets when they're out in the open space after seeing her tall visage. She makes her presence known with her signature laugh "Po, po, po…" with a somewhat masculine voice."