A new and unique x Mangave plant named ‘;Iron Man’; characterized by a large mound of broad, fleshy, longitudinally folded, grey-green foliage that is cascading or arches with age. Leaves have large, firm, marginal teeth that leave an imprint on the top and bottom of surrounding leaves in the enrolled apex. Foliage is upright to outwardly toward stem with a tendency to arch in maturity. The new plant is suitable for the garden or as a potted plant in the garden or home.