Episode 18 was nice and rather lighthearted I felt. I'm glad it had a happy ending, and the part of Ginko getting up from the ground was funny (for a moment I tot it was one of those buried in the landslide emerging in zombie form by some action of the Mushi). And later on when he sold the "real" coat to his pal, especially impregnating only enough of the Mushi to cause it to smoke once in ten yrs, that was funny too. Smart move, and reaffirms my conviction not to buy anything from Ginko.
I don't think the Mushi's entrance/relation was rushed, this is an episode where Mushi aren't really the focus, after all, it
is a common Mushi.