GuroKawaii. "Kawai"i means "cute" in Japanese. Guro stands for gory (grotesque and sadistic.) Article by Brian Ashcraft for Kotaku explains the phenomenon - a reaction to a culture with perhaps too much "cute" in it for some.
What exactly is Mameshiba? They're not quite a bean, nor a dog but rather a hybrid of both. They love to appear out of nowhere and offer random bits of trivia whether you asked for it or not... Oh mameshiba, how much I love thee.