One of the many charming aspects of Stan Lee's Marvel Comics was the good-natured "David & Goliath" rivalry he and his staff (i.e. "The Marvel Bullpen") had with mega-publisher DC Comics. You see, back then things were exactly opposite of what they are today, with DC Comics as the 800-pound gorilla and Marvel the scrappy upstart.
Tweaking a common advertising convention of the time (in which competing products were only referred to as "Brand X"), Marvel would playfully refer to DC Comics as "Brand ECHH". In 1967, Marvel even rolled out a superhero satire title named Not Brand Echh, mocking both their own characters and those of their endearingly-square competition.
However, not everyone was amused by the Brand Ecch stuff. Take Steve Gordon's letter in The Amazing Spider-Man #56 (1968) for example (click to enlarge)...
And there it is: the gauntlet thrown. So...what do you say to that confrontational Brand Echh acolyte, Stan...and are you going to stand for that brainwashing charge?
Oh, OOUUCHH! Touche', my man Stan...answering the brainwashing charge with a wry implication of mental illness!Oooof!
A little feisty, sure...but can you blame the guy when he had to read so many of those confounded multi-page letters?