A unique battery-shaped Aragami which clings immobile to the ground. Though no one has ever seen it in motion, the fact that it exists worldwide makes it more than likely that it moves along the ground at night. Armed with precise, long-range laser and a close-range poisonous needle. The best plan of attack would be to sweep behind it and land a crushing blow.
The Cocoon Maiden species are one of the two immobile Aragami in the God Eater series, the other being Night Hollow. Cocoon Maidens are believed to move by tunneling underground (a theory supported by the fact that they spawn from the ground).
Cocoon Maidens are often used as special targets in certain missions for God Eater Burst (e.g. in "Quick Draw" and "Here, Here, Here"), most certainly because of their incapacity to move.
Cocoon Maidens are based on the (likely fictional) medieval torture device known as the iron maiden.
In GE2, their attack pattern has become much faster compared to GEB Thus it's a bit harder to get to them as they shoot a lot of their lasers at you.
If you were to be hitted by its needle, it can cause Jammed status effect (the radar will be messed up).