EMMA FROST

During the Utopia war with Norman Osborn's Dark Avengers, the X-Men's most dangerous opponent was an ally: the Sentry, whose godlike power came with the Void, a murderous second self. Emma's counter-move, in Dark Avengers/Uncanny X-Men: Exodus Vol. 1 #1 (2009), was surgical — she entered the quiet ‘white room’ she had previously built inside the Sentry's mind and held the Void there long enough for Bob Reynolds to flee the battlefield entirely.

The Void did not stay held. It tore free and chased its host — but a sliver of it sheared off and lodged in Emma Frost's forehead. That splinter was a live wire: if it reached her telepathy, the Void would gain an omega-level psychic as its new puppet. So Emma did the only safe thing. She turned to diamond — the one form in which she has no telepathy at all — and she stayed there.

For weeks of story time the White Queen walked Utopia as a statue of herself: unable to read a single mind, cut off from the sense her whole life was built on, guarding a splinter of cosmic evil behind her own brow. The extraction, when it finally came, needed Professor X to bridge her mind to Cyclops — and the Void simply changed prisoners, lunging into Scott Summers, who locked it inside a black-box prison in his own mind and carried it there instead.