It looks scary, whatever you deem that as
You see, no matter how you look at this, there are few things as subjective as fear. Some people will panic at the sight of a spider, others will actually cry if left in a cramped space, and many were once scared of the dark. In other words, something that is scary to one person is not necessarily scary to others. Therefore this question can't be truly answered...or at least not with a definitive physical description of a creature.
Your creature, putting simply, has no and all shapes. It has incredible psionic powers and the ability to shape-shift. It can easily find out what one is most terrified about and appear to them as exactly that. Someone with arachnophobia would perceive the monster as a colossal spider or a swarm of spiders, while someone scared of the dark would see what appears to be a growing shadow that lurks towards them while absorbing all light it finds in its way. This process is almost instantaneous and can be applied to several individuals at once. If it so desires, it can even affect the senses of their victim, in order to further terrify them. It could even fool one into not being able to perceive its presence, luring them into a false sense of security before utterly crushing the illusion.
Now, why noses? Because that's how it finds its prey. Despite its incredible abilities, the creature is very poor at recognizing its targets (which isn't that odd when you think at how much it might take to constantly change shape and influence the senses of the creatures around you). Just looking at what something is scared of is not a good way to indetify your prey, because everything is scared of something, but noses? Those are different, and humans especially have distinctive qualities at this region that make them much easier to tell apart from all the other things. A mask that covers the mouth and nose also hide a large amount of the face, and can make identifying an individual hard even for us humans, let alone a shape-shifting cryptid which had to use most of its brain power into being able to use telepathy and influence its own shape and other's perception of it.
There you go. Something that's technically an animal, needs noses to attack and will look scary no matter who looks at it. Is it a real animal? No. Could it exist in our world? Most likely not, at least not with earth biology (I am aware of mimic octopuses, but I don't think they can inflict a sense of claustrophobia). If what you wanted is a realistic animal that can scare everyone,you're out of luck, because there are people in this world which sees parasitic animals as incredible but not scary at all, and that applies to basically all fears and phobias out there.
The problem with what you want is "simple" : you want something that can trigger a displeasing subjective feeling in every single human and also hide so well that we somehow cannot hunt it to extinction (even if we're talking small animals, most creatures will react badly to some kind of chemical, and you can bet humans would be more invested in finding this chemical than achieving world peace). In other words, you need something which can change how people perceive it and which is capable of essentially disappearing so that it can't be tracked, hunted down and killed off.