Thread:BlueFrackle/@comment-34769545-20190416195117/@comment-1197011-20190416201354

I don't recall Slenderman being identified as an alien in any of his "official" appearances (certainly not in the 2018 film; though it's been some time since I've played the Slender games). But you can make a page for him on Non-alien Creatures Wiki if you wish, using info from "official" sources.