15Groot Was Originally a Villain
As far as monosyllabic sentient tree creatures go, they don't get any more heroic than Groot (sorry Ents). But when this wooden giant first lumbered onto the scene in 1960, he was as evil as plants come. (Save for maybe poison ivy. That stuff is the worst.) In fact,
Groot was nothing more than your run-of-the-mill monster looking to terrorize the planet, like Dracula, King Kong, the Blob, or Justin Bieber.
Groot was created by Jack Kirby and Stan Lee, and debuted in Tales to Astonish #13 where he was hailed as the “Monster from Planet X.” Surprisingly verbose for a walking tree, Groot spends much of his time talking about how terrific he is and all the different ways he's going to defy humanity. This includes such grandiose plans as conquering a small village and subjecting its townsfolk to experimentation on his homeworld. Fortunately, there is a biologist around to stop him. Putting his college education and girlish name to good use, Leslie Evans quickly breeds super-termites overnight to chow Groot to death. In true Groot fashion, he would return over a decade later in Incredible Hulk Annual #5 to fight the Green Goliath. As expected, Hulk smashes bad guy Groot in the most ridiculous way possible.