The pilot in command (PIC) reported that he executed a normal approach, following an instrument proficiency check. He reported that during the landing flare the flight instructor, "grabbed the yoke and pulled up," and he heard a loud thump. The PIC reported that he thought the flight instructor was performing a go around, however the flight instructor said, "we hit a deer and must not go around." The airplane settled to the runway, the right wing "dipped onto the ground" and slid to a stop. The airplane sustained substantial damage to the right main landing gear attachment point. The PIC reported that he exited the airplane and saw the right main landing gear and the deer on the runway near the intended touchdown point. The pilots reported that there were no mechanical malfunctions or anomalies with any portion of the airplane prior to striking the deer.