The baneling egg is a zerg pupal in StarCraft II, being the transition unit between zerglings and banelings. A baneling egg uses a different model than standard zerg egg, and glows green until hatching.
Banelings are created from zerglings following a brief chrysalis phase. The appearance of the baneling egg is an immobile baneling, which gains movement after the mutation completes.
Zerg Units and Structures of StarCraft II
units and structures