Coma Niddy's rap about dark matter:
On the clip's YouTube page you can click "Show more" to see the lyric and additional information about Coma Niddy (Mike Wilson), the writer-performer-producer, including links to his other science-related rap songs.
I have one minor quibble with one of his other songs, the one about string theory. He says, quite correctly of course, that string theory is a theory and hasn't been proven yet. This unfortunately reinforces a commonplace misconception about the use of the word "theory" in science. In ordinary conversation we tend to think of a "theory" as a hypothesis or intelligent guess, but in science the word often means something more like "systematic explanation." A "theory" in that sense can indeed be tentative (as with the various forms of string theory), but it can also be known to be incorrect (e.g. phlogiston theory in chemistry or aether theory in physics) or even very solidly supported by evidence, such as the germ theory of infectious disease or the theory of gravity or the theory of evolution by means of natural selection.
And while I'm on that general subject (and not talking about Coma Niddy here, since I'm sure he knows this at least as well as I do), a related and even more confused notion is that once a theory becomes established it qualifies as a "law." In fact, a "law" in the scientific sense is just a succinct rule, such as the various laws that are part of thermodynamics. Laws are in fact often limited in their applicability. Ohm's Law, for example, works for simple resistors but not for, say, a Zener diode. And the classical Rayleigh-Jeans law for the spectrum of black body emissions fails so spectacularly (even ridiculously) at short wavelengths that its failure came to be called the "ultraviolet catastrophe" and necessitated the development of quantum mechanics.