These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Nightmare Fuel: "Cat and Mouse" (vol2 #87) was about Jubilee being left to fight an Ax-Crazy Sabertooth after he kills both Bishop and Beast. As the story progressed Sabertooth received more and more physical damage, verging on Body Horror, as Jubilee is left to fend for herself in a version of the Xavier Institute which verges on H. R. Giger levels of nightmarish design. The issue was voted one of Comic Book Resources' "Scariest Comic Books Of All Time". See here.