Was Gregor hurt by an apple or What…?

“In Franz Kafka’s “The Metamorphosis,” the apple thrown at Gregor by his father symbolizes the decaying relationship between Gregor and his family. After Gregor emerges from his room, his father throws apples, one of which becomes embedded in his back, causing him pain and further isolating him. The rotting apple symbolizes the deterioration of Gregor’s family relationships and his own decline.”