Yay! See M, I was right!
From the Wiki
Kuromi (クロミ Kuromi?) is the rival of My Melody from the animeOnegai My Melody. She is a white rabbit-like creature, wearing a black jester's hat with a pink skull on the front and a black "devil" tail in the place of a normal rabbit's tail. Kuromi's appearance also looks similar to those of cartoon characters from the 1920s and 1930s. Goods featuring Kuromi first appeared in Japan in July 2005. She has three image songs all sung by her seiyū, Junko Takeuchi.
