Nightmare Fuel / Book of the New Sun

• Jolenta's eventual fate. Originally a homely woman, Dr Talos made her very, very beautiful. So beautiful that Even the Girls Want Her. It's left vague exactly how he did this, but strongly implied to be the reason why she's so weak and lethargic all the time. Then he and Baldanders leave, and the treatment starts to break down, and Severian feels metal bands under her skin holding her body in shape.
• The Alzabo, an apex predator like the cross between a bear and a lion that absorbs the minds of its victims, then uses those voices and personalities to lure their loved ones. Its speculated the personalities it eats are technically still “alive” in a sense, but it’s never made clear exactly what its like being “alive” inside an Alzabo.