Be afraid. Be very afraid.
Unless Walker is a spider, a clown or some kind of sentient mannequin with a mind of it's own I have no reason to fear him 
What is he is all three of them?
And why would you fear those three?
My five phobias are Coulrophobia (fear of clowns), Arachnophobia (fear of spiders), Automatonophobia (fear of things that falsely represent sentient beings, but in my case only people), Thalassophobia (fear of open water/large bodies of water, most notably the sea) and Thantophobia (fear of losing loves ones).
The fear of losing loves ones is obvious, the fear of open water I think comes from two things. I nearly drowned as a child once and even before said event depth, murkiness and the great unknown beneath your feet have been utterly terrifying concepts to me.
I'm not sure if a specific event triggered my fear of clowns or it just developed over-time as I've always seemed to have feared the bastards, the same goes for spiders and all the stuff that goes under Automatonophobia.
Seeing as how Walker cannot physical be open water/a large body or water nor can he be losing loved ones Thalassophobia and Thantophobia can not apply to him.
My idea of hell is a large/open body of water either containing a large creature that is a mixture of a clown, a spider and mannequins or some kind of creepy looking dolls or dummies that eats your loved ones right in front of you or a open/large body of deep water containing sentient mannequins or creepy looking dolls full of large spiders while the only way out is a boat full of clowns that toss your loved ones overboard to drown or die another grizzly death right in front of you. While the clowns laugh as well.
And I've just given myself nightmares. Fuck my imagination.
, and quacks like a 