It has fast movement speed, high health, high damage output, decent range, hits multiple cats, and can do a Critical Hit sometimes. Metal Cat won't help much when it does. All in all, a devastating enemy. Bahamut Cat might be able to help you out...
Don't use Awakened Bahamut against R. Ost; because of his short range, he'll almost always get killed or knocked back before he can hit R.Ost.
Dark Mitama can easily perma-slow this avian atrocity from long distance, rendering it powerless.
Stressed about recent hair loss. Yes, his last name is actually Ost. His first name is Rich. Can critical sometimes.
Recently, hair loss began to worry
Ostrich club. By the way in until the ostrich is the same last name, good meeting is the name. Sometimes it unleashes critical.
A Metal enemy that only appears in the Golden Week and Silver Week events. It drops less money and has the usual Metal ability of only taking 1 damage except for Critical Hits, but it has much lower stats all across the board and cannot perform Critical Hits itself.