Answer:
The moment Gregor turns into an insect and is attacked by his father.
Step-by-step explanation:
Kafka, the author of "Metamorphosis" had a very bad relationship with his father. This can be seen in the letter he writes to his father, where he shows how he felt attacked, ignored and without a chance to speak up and justify himself. This is also reflected in Gregor's relationship with his father in "Metamorphosis" because when Gregor is turned into an insect, his father attacks him violently, without letting Gregor explain the situation and without Gregor being to blame for what happened.