Ikuta-sensei's Science Classroom - S1.E13

Geo meets Mitch Shepard, a science teacher, and a classmate, Pat Sprigs. He attends one of Shepard's classes and becomes excited about making bottle rockets for the next session. However, that night, the FM-ian Libra appears and Mega Man injures him in battle. Libra escapes into Shepard's Transer and takes over his body, hiding until his injury heals. He then tries to live Shepard's life normally, but the suspicious activity attracts Geo's attention. The two end up battling when Libra transforms into Libra Scales, but because of his injury, he is easily defeated and Shepard is returned to normal.