LOL,,one pound of anything is still one pound. We have no clue what dark matter really is, perhaps a black hole.
An entity so dense there is no space within it, not even between atoms it consist of or even space within the atoms.
It has no energy, or more accurately, can't escape its gravity. Only mass, like the mass of the earth the size of a marble. Gravity remains, a function of mass.
That could mean a volume of a cubic centimeter could easily weigh over 10,000 pounds.
I think you misinterpret what Dr. Farnsworth was saying, that or his babble, just nonsense.