for what it's worth 1: I recall reading somewhere that Proudhon - whose views were largely founded upon his admiration for small communities of peasants or craftsmen and who wrote of social contract in almost mystical and religious terms - referred to Marx as 'tapeworm of socialism', claiming that M infiltrated movements that owed nothing to his efforts.
for what it's worth 2: Marx's criticisms of Proudhon in _The Poverty of Philosophy_ were regarded favorably by Bakunin who preferred term 'collectivist' to 'anarchist', in part, to disassociate himself from Proudhon. While I don't recall whether or not B refers to M or P as a worm (or vice-versa), I do recall that Marx employed word 'anarchist' perjoratively, indicating not only utopian impracticality but targetting those he thought wanted to destroy First International, and his target was most often Bakunin. Michael Hoover