chrysalis (n.)

"form in the life-cycle of butterflies, moths, etc., between larval and adult, consisting of a dormant pupa in a hard outer case," also the case itself, c. 1600, from Latin chrysallis, from Greek khrysallis (genitive khrysallidos) "golden colored pupa of the butterfly," from khrysos "gold" (see chryso-), + second element meaning something like "sheath." Seeking a plural, OED leans toward the classically correct chrysalides."