Over the years, McDonald's hasn't just introduced America to things like the Big Mac and the McRib, they also created a bunch of different characters. Of course there's "Ronald McDonald," the chain's clown mascot, but there are others as well, like the "Hamburglar," a villain who loves to steal burgers, "Mayor McCheese," a hamburger-headed politician, and then, there is "Grimace," a purple blob-like being.
"Grimace" made his debut in 1971 as the "Evil Grimace," who loved to steal milkshakes and sodas with his four arms and hands. However after a year, the "evil" was dropped from his name and he was rebranded as a good guy with only two arms. But what exactly is he? McDonald's has never really revealed that, but Brian Bates, a long-time manager at a McDonald's franchise in Canada, explained what inspired the purple character.
Bates went on to state that his explanation is "unofficial."
The closest McDonald's has ever gotten to giving "Grimace's" origin story was in a tweet where they wrote, "'Grimace' lore says he is the embodiment of a milkshake or a taste bud."
You can read more of what Brian had to say here.