This is one of those cases where there are two hostas with the same name. One is registered and, therefore, the "official" version of H. 'Cosmic Rain' while the other is a non-registered plant and needs to be renamed to avoid further confusion.

A large size (21 inches high by 39 inches wide) hybrid of H. 'Frosted Morning' × H. 'Beer Belly Blues', this cultivar was registered by Rod Kuenster of Iowa in 2013. It has medium blue-green foliage that has streaked variegation of pale yellow, greenish white and creamy white. The leaves are broadly ovate, slightly wavy, slightly corrugated with a slightly shiny top with streaked petioles. Pale lavender, tubular flowers with medium lavender stripes bloom in August. It sets viable seeds.

Hosta Helper will call this plant 'Cosmic Rain' (Kuenster)

Originated by Jim Spence of Canada, this non-registered cultivar is of unidentified parentage. A flower of this plant is displayed on The Hosta Library website with no further information. The flower is dark purple in color and has yellow stamens.

Hosta Helper will call this plant 'Cosmic Rain' (Spence)