The question is somewhat complicated as it depends on what you mean by "create" and your definition of communism. 

Foucault, in his frequently cited essay, "What is an Author?", talks about intellectual movements he calls "discourses", such as Marxism, Freudianism, and Christianity, which are distinguished by having an unitary "authority" to which they refer and which function as totalizing hermeneutics. Marxism, as such, acts as one of these "discourses" and is grounded in the authoritative texts of its founder, Karl Marx.

However, as pointed out by the other answerers, the term "communism" is broader and refers to some ideas created by Marx, but is not so exclusively dependent on Marx as an authoritative figure.

The term is often associated with the 1848 Communist Manifesto, which was co-authored by Karl Marx and Friedrich Engels. It combines the historical and theoretical work of Marx with Engels' detailed empirical studies of the new industrial working class in the great manufacturing towns of England. Marx himself sees his work as building on historical investigation of "agrarian communism" and application of those concepts to modern industrialized society. Earlier models of agrarian communism can be found in many Christian groups such as the Diggers and Levellers of the seventeenth century. In the twentieth and twenty-first centuries, the term "communism" is applied to Russian Leninism and Chinese Maoism, which are variations on Marx's ideas. Many countries that call themselves communist actually practice "state capitalism" or totalitarianism, which are not precisely what Marx had in mind. 

Strictly speaking, Karl Marx's specific philosophy should be termed "Marxism," as both modern Communism and Socialism diverge from his ideals in several key ways. However, Marx created the concept of  communism as a political and economic theory, with his book The Communist Manifesto being his essential explanation of a communist (Marxist) society. The Communist Manifesto and the many interpretations of it fueled many revolutionary activities during Marx's lifetime, although most of these were failures; Marx in his letters explained that he didn't necessarily agree with all of his conclusions, nor of the actions and results of implementing similar systems around the world. One of Marx's most important followers was Vladimir Lenin, whose ideas helped form the Russian Revolution. Marx's ideology remains a strong political force today, and his name is either a compliment or an insult, depending on personal beliefs.