Just Rhombo in a yukata. A yukata is a traditional Japanese robe somewhat akin to a kimono. It used to be common to see for a time in Japan, but it's now largely phased out for more modern clothing. Rikishi have to wear this in public (along with sandals) most of the time due to the rules of sumo.

Of course, the big guy had to get diamonds on his yukata. ♦

Oh and the kanji and katakana: 力士狐:ロンボ says "Rikishi (sumo wrestler) kitsune (fox), Ronbo (Rhombo)

Rhombo ©  super-dough-mutt