A new and unique X Mangave plant named ‘;Whale Tale’; characterized by glaucous, silver-grey, slightly-arching, lanceolate foliage with small semi-flexible marginal teeth on deeply-scalloped margins and apical spines. Leaves develop greyed-purple spotting with strong ultraviolet light. The habit is low, wide and slightly arching. Plants are useful for landscaping as specimens or en masse or as container plants in the landscape or in the home.