Banshee Egg Stone
From Creatures Wikia
When the grendel update is installed on docking station, the banshee grendel stone appears in the Workshop, and periodically spawns banshee grendel eggs! Banshee grendels are always in a constant state of anger..
Banshee grendel eggs are a similar color as the stone, and have a similar "B" on them.
In C3 standalone banshee spawn below the creator and replicator from the same stone.