Since learning a bit more about Marxism, the question has been opened in my mind, to what extent a common perception of what a communist society is supposed to be like - for example, the USSR - is something that matches what Karl Marx himself actually explicitly discussed in his theoretical writings.
I believe, for example, there is a quote that is commonly falsely attributed to Marx: “The last thing the capitalist will sell us is the rope we hang him with,” or something. In other words, it is at least possible that something bordering on “McCarthyism” has affected modern public understanding and perception of Marxism, perhaps at least in the Western world - possibly, through straw man arguments, what is decried and dispelled as “Marxism” is not actually what Karl Marx said or advocated. Thus, Marxism may be vilified, but unjustly, because the thing that is being countered may be bad, but it may not be (authentically) “Marxism”.
Since leaning towards this conviction, I have been forced to acknowledge that I really don’t know very much, either about what Marx actually wrote, as well as what communist states that arose were actually like. It is possible that Marx’s political leanings may have been more in that direction than I realize.
So, what is the disparity between “Marxism” vs. “communism”, as commonly known? How similar or different are they really? With textual evidence, what can we know Marx actually believed or advocated?
By far the most important thing in answers to this question is textual evidence. Please show what Karl Marx actually wrote, in addition to what orchestrators of communist states, like Lenin or Mao, actually wrote, or actual laws or policies they had.