Changeman Episode 43: Super Giluke and Episode 44: Leave it to Mai.
The first of these two episodes is a great cap to the Nana arc this time around. So Giluke went from being a cyborg, to a ghostly beetle, to a vampire. How come there isn't a pokemon evolution like that?
The second is an odd one for me. I loved the cosplay episode of Gokaiger, but something about Giluke's idea of a Ghost Town being a wild west town is rather offputting.
Really, there's only been one piece of Mai's personality that's been meaningful, and that's the fact that the man she loves is out in space somewhere. Being a cosplay goddess and a biker are not on the same level of character information as everything Sayaka has.