Everybody called Blackstone Penitentiary “impregnable,” which Rocko took as a challenge. After months stealing industrial chemicals from laundry duty, janitorial work and the maintenance shop, the self-proclaimed genius finally unveiled his latest invention to his cellmate Earl.“One blast of this stuff," Rocko boasted, holding up a glowing vial, "and we’ll see just how 'impregnable' this joint really is!”Unfortunately, the formula didn’t make the prison less impregnable… It made Rocko and Earl impregnatable instead, and the explosion instantly transformed both hardened convicts into pretty young women with great big baby bumps.In the end, Rocko and Earl did manage to get out of Blackstone Penitentiary… when they were transferred to the prenatal wing of the state women’s prison!