In both texts, the characters experience an unpleasant change:
In "The Metamorphosis," Gregor transforms into an insect with "many legs" and "snapping jaws"; neither he, nor his family members know how to cope with his new form. He feels abandoned by his loved ones, who simply cannot come to turns with Gregor's altered state.
The woman in "The Mirror" also deals with the unpleasantness of seeing her reflection change from that of a young, lovely girl to an old woman. Although this situation is admittedly less extreme than Gregor's, the character resents growing older and compares her older reflection to a "terrible fish."
Both characters cannot escape from their change:
Both of the characters in these texts experience a real sense of finality with their transformation; there is no going back to how they were before. Gregor and the woman in the mirror must come to terms with how they have changed. Gregor's mother resisted the idea of moving his furniture:
"and is it not so, that we, as it were, are, through the removal of the furniture, signifying that we are giving up all hope of recovery and are inconsiderately leaving him to himself?" (Chapter 2)
The irreversability of the transformation leaves both characters desperate, knowing that the only release may be through death.