An internet pop culture horror - in a published work?

I'll cut to the chase. I am writing a comic that I intend to self-publish, and I am intrigued by The Slender Man (and will not accept responsibility for any nightmares and paranoia resulting from looking him up!). If I recall correctly, Slendy was created by the Something Awful forums, and slowly gained popularity, notably through the Marble Hornets collection of videos and blogs. Those videos are now out on DVD. Apparently.

My main character has a personal vendetta against him, as the premise is that Slendy dragged her sister away and returned her, dead, with her insides bagged up in plastic freezer bags. (Inside the body, with no evidence of entry points. Poetic licence!) The MC spends a large amount of the story pondering him and working out how to take her carefully calculated revenge.

What I'm wondering is - while I don't think anyone really has a claim on Slendy, will it upset other people if I use him? Can I get away with a thinly veiled tribute to him, and just describe him as "a tall faceless man"? Any other thoughts and opinions are welcome too.

He's sort of a strong theme in the story, but not necessarily the central one, if that makes sense. In any case, I hope it's okay to post here! It's not exactly a novel, but I think it takes all the same planning and characterisation... thanks for any help in advance!

I think the best idea would be, as you say, to refer to him as a "tall faceless man" and things like that. I don't think anyone has copyright on Slendy, but my thought is that if you do it as a kind of hidden reference, people who don't know what Slenderman is all about will get it too, and people who do know will get it. That way, you can reach out to more people.

Or you could do like they do in Marble Hornets and refer to him by a different name, like they call him "The Operator".