This wriggling mass of derp is Magikarp, Pokemon's ultimate useless Pokemon. The only attack it was capable of learning the original games was "Splash", which was a completely useless move. Actually, "Splash" was an erroneous translation of the Japanese word for "Hop" but that is neither here nor there. Of course anybody who knows anything about Pokemon also knows that Magikarp eventually becomes this mass of epicness:
Gyarados will have his revenge.
What some people may not know, is that Magikarp and its evolution are based on Chinese mythology. There is an ancient Chinese legend that talks of a mythical Dragon's Gate atop a waterfall. The ancient tale claims that any carp which is strong enough and brave to jump over the gate is instantly transformed into a dragon, hence the reason Chinese dragons have carp-like features such as scales. Magikarp was originally only able to learn the move "Hop" in reference to the jumping carp of legend.
The legend is further referenced in the Nintendo 64 title Pokemon Snap. In the "Valley" level the player is able to grab a picture of Gyarados only after tormenting a Magikarp until it jumps into a waterfall. At that point it evolves and comes out as a Gyarados, as you can see below:
Thus we learn that we should never judge a book by its cover. Even the lowliest of carps may someday become mighty dragons. Or maybe we've learned that you should be careful of who you bully, because you never know what kind of monster they will become.
Especially if they have just had their first period and are living in a Christian fundamentalist household.