13 feat of Hercules. What do we call the 13 feat of Hercules, what exactly is he talking about?

There was such a Greek titan Hercules, who performed the twelve labors of Aeschylus, and thus earned his freedom. The feats were different, but very difficult. And the thirteenth feat was accomplished by the hero of this work, only in a figurative sense. The hero was so reluctant to have a math lesson because of his homework that had not been done, that he called the nurses to the class to get everyone vaccinated during the lesson. However, the teacher understood everything and made fun of the hero’s deed, calling him the thirteenth feat.