Today's DC Superheroes Series 4 Brainiac review told how, like Lex Luthor, the character was redesigned for Kenner's Super Powers line, but the design was also put into the comics, in 1983's Action Comics #544.
During the pitch process for 1984's Series 1, Kenner showed art of the characters they planned to make. While most of the characters were just copies of official art, the redesigns were still in-progress.
Brainiac's head already had that "octopus mantle" shape, though a bit more pronounced, but the biggest change is that rather than being purely silver, he was a few different shades of grey with a red body! Quite different than what we know now, 30 years later.
