White Flag: the Substance's smily-face mask comes off
this Substance you thought was your one true friend, that you gave up all for, gladly, that for so long gave you relief from the pain of the Losses your love of that relief caused […] has finally removed its smily-face mask to reveal centerless eyes and a ravening maw, and canines down to here, it’s the Face In The Floor, the grinning root-white face of your worst nightmares, and the face is your own face in the mirror, now, it’s you
Context
The theme's governing image, stated at the pivot of the Bottom-narrative: the Substance has been wearing an ironic mask the whole time. "It's midnight now and all masks come off," and the jolly have-a-nice-day face the Disease presented — the same "smily-face" that will recur as the cartridge's emblem and as the mask on Joelle's veil — peels away to show the maw underneath. Irony here isn't a rhetorical stance; it's figured as the literal disguise of the thing that's killing you, a smiling surface over "centerless eyes." And the horror twist is that the mask is finally your own — the ironic distance you thought protected you turns out to have been the predator's grin worn inward. This is why the unironic clichés matter: they are the only register that names the maw as a maw.