From Don Markstein's Toonopedia:
Unlike most parody publications, Not Brand Echh had continuing characters. Charlie America stood in for Captain America, The Inedible Bulk for The Incredible Hulk, Mighty Sore for The Mighty Thor, Scaredevil for Daredevil, etc. Eventually, the title fielded a resident superhero of its own, Forbush-Man (aka Irving Forbush, another letter column schtick, this one going back to 1955). The latter, in the grand tradition of superhero spoofs (e.g., Supersnipe, Captain Klutz, Super Goof), wore red long johns as a prominent element of his costume.
By the ninth issue (December, 1968), it appeared Not Brand Echh had become a sales sensation — that was the first in its new format, extra-thick but costing about twice as much as most comics. But perhaps not, as the next one, billed as "The Worst of Not Brand Echh", consisted entirely of reprints from early issues. After #13 (May, 1969), it was canceled.