Justice League Action (2016)

S1E24 Battle for the Bottled City

The Atom reduces Superman to a microscopic scale, allowing him to infiltrate the Bottled City of Kandor. However, when Brainiac invades the Fortress of Solitude, overpowers Cyborg, and seizes the bottle, the Atom finds himself alone in the fight against Brainiac, needing to step up to the challenge.