According to 5e lore, the Mind Flayer / Illithid lore reproduces via ceremorphosis: a tiny illithid-creature eats its way into the (sentient) target's brain, forcing transformation to occur some time later.
Under what conditions is this either preventable &/or entirely reversible (Regeneration or Mind Protection rings, restorative / regenerative spells, back-up clones, polymorphs… anything at all)? Is there, once again, nothing lower level than Wish to solve this?
This is valuable for DMing & story-construction: many transformed illithids might / would / could miss their previous existence (such as an Illithid Arcanist and mindwitness.) If such a reversal is possible, it would be fine to know.