![2girls be_nantoka extra k-on! kinoshita_shizuka kotobuki_tsumugi lifting multiple_girls open_mouth rock school_uniform strong track_suit rating:s score:6 post #731138](/cdn_image/preview/24/45/2445cefbee3e2c69133cbabda481483c.jpg)
A pool for pictures showing Mugi being stronger than most girls her age, any girl her age or even stronger than any normal human could hope to be.
The name of the pool is most likely a reference to the stereotypically simple manner of speech displayed by the superhumanly strong, but simpleminded (depending on the author) Marvel comic book character Hulk.