Punching the ball: By using multistep chemical reactions as a “can opener”, a half circle opening is cut around a pentagon in C60 to form an open‐cage fullerene with an 18‐membered orifice. During the process, one carbon atom in the fullerene skeleton is eliminated into the cavity as carbon monoxide to form a stable endohedral complex CO@C59O6 (see figure). The single‐crystal X‐ray structure shows that the trapped carbon monoxide has strong dipole–dipole interaction with the cage.