It's this pulsating, shifting thing. Hard to describe. A million little planes folding in on one, oddly flat. Not really colorful. Not sharp, or soft. It seems to move when she looks at it, but it never leaves the spot. There aren't any points to it, it's this one mass that moves in and out of itself. Hanging there, floating. This mass of pain, floating right in front of her.
She surveys it for a while, walking in circles around it. No matter what, it always seems to face her. It's not too large (maybe twice the size of her face) but it's dense, she can tell. She knows some of this without having to ask or ascertain, like it was meant to be, the mass of pain in front of her. Everypony's pain, all the pain anypony ever felt, will ever feel. It's silent. It makes her feel sick. Every bad thing that will ever happen feeding into this mass.
It seems to suck in the light around it, it casts no shadow but the air is darker nearby.
She understands pain. That's why it chose her. She knows what pain can do. The pain wants to be hers. The pain is tired of making everypony hurt. The pain wants to let her hurt instead. Let her take in the dense, queasy mass, let her rot the flesh and swallow the bile, and then let everypony else be free. Let them be free of pain forever.
It makes her sick and weak and scared and small but she's honored because she knows that deep down it's the only thing she ever wanted.