It's either the joke is Admiral mistaken Halloween for Christmas (Hey, it's Jack Skellington-ish) Or the Sandy Claw Santa Claus costume is intentional, as it is the least expected.
I'm sure this belongs in stupidly clever, but there's should also be another pool this should go in (if you think about it for a sec it's obvious, but idk if there's even a pool for that)
Oh my, sorry - can you wait a bit?
You're pretty early, aren'cha?Sweets, right?Usshisshisshi...October 31st
HalloweenIt's Trick or Treat.Does her stomach hurt?Oi, Inazuma...Totally shocking, it was.-Tenryuu-Sorry to keep you waiting, kiddos.The day the shipgirls are permitted to freely wear costumes, once they're done with sorties.Let's give her the flattest reaction that we can muster then...We've come to search the premises!That's probably the Admiral putting a costume on too - she's probably going to try to give us a shock...Admiral, I know you're in there!Sweets!MUSHIKINGAn arcade card game about collecting and battling beetles.Huh?
What're you doing in there?