10 Justice League Villains MORE Powerful Than Darkseid
The O.G. - The first villain to face-off against the Justice League of America back in 1960 was a one-eyed giant starfish with mind-control powers, Starro the Conqueror.
In his first appearance, Starro absorbs a nuclear blast, consumes the brain power of scientists, and controls the minds of thousands of people, only to be defeated by some quicklime. What a comedown.
He doesn't have the physical gravitas of Darkseid - as an alien-shaped-like-a-fish-shaped-like-a-star - but he's brought the League to the brink on several occasions, notably during Grant Morrison's nineties JLA series, when they have to enlist the help of Dream himself to overcome the stellar nuisance.
More recently, a small tissue sample of a defeated Starro was cultivated by Batman in a jar, resulting in a smaller, friendlier version assisting the Justice League under the name 'Jarro', who calls Batman 'Dad' and dresses up like Robin. Because sometimes it's nice to be nice.