The Black Beetle is a rare NMC. They can be very dangerous, they do deal good damage and approach Aya fairly quickly. They also have insanely high defense which prevents them from taking much damage from most attacks. Buckshot and Electrical attacks like Apobiosis and Plasma can knock them over, allowing Aya to attack their underside, which allow you to deal much more damage. The targeting system is a bit of an issue against them so be careful. After a while, they will flip back over and need to be knocked back again.