The following contains spoilers for Young Justice: Phantoms Episode 21, "Odyssey of Death!" now streaming on HBO Max.
Young Justice: Phantoms made the Justice League's trip to New Genesis quite enlightening. Jay Garrick had his first official mission since becoming The Flash, while Rocket learned about leadership and moreso herself. Seeing Orion dealing with his inner demons helped her understand that she needed to better relate to her autistic child Amistad back home.
However, the mission also became dangerous after Lor-Zod emerged, trying to power up the Phantom Zone projector that the incredibly ridiculed Mantis had stolen. Their goal was to free General Dru-Zod, but that's not exactly what happened. In the process, the show set free a different character that came off as very similar to the Celestials from Marvel's Eternals -- continuing comparisons between the DC series and the Marvel Universe.
Lor-Zod took his projector to the Boiling Lake to absorb heat energy in hopes of using it to open a portal to bring Dru-Zod back. However, his plan was interrupted by several heroes who didn't want to see Lor-Zod's father return, including Green Lantern's Kilowog and Tomar-Re. A fight broke out and the the chaos activated a Promethean -- a giant statue that rose up from the forest.
In comic canon, these giants tried and failed to breach the Source Wall to discover the mysteries of the cosmos. The Prometheans ended up embedded in the wall or in meteors as a result. They were left suffering as a reminder to the public not to play god. But in Young Justice, the Promethean spewed cosmic fire into the atmosphere in an attempt to incinerate the entire planet.
This sequence in "Odyssey of Death!" felt like DC's version of the Celestials emerging from the core of planets in Eternals. They'd rise up, feed off the essence of the planet and power up before they destroyed these places. The planets they consumed essentially functioned as an incubation chamber for them. The Promethean was also trying to remove life -- but not to drain the planet of its energy. Instead, it was trying to protect the planet from invasive species... such as the heroes and villains.
Thankfully, Tomar-Re would funnel the flames out (dying in the process) while the Legion of Super Heroes blew the projector up, which allowed the being to sleep again. Had they not done so, Orion and the League had little hope of stopping the Promethean. They couldn't tap into its mind or sever its connection like the Eternals had with Tiamut. Instead, the New Genesis mission would have ended with the whole planet being turned to ash... not unlike what viewers saw in Eternals.
New episodes of Young Justice: Phantoms debut every Thursday on HBO Max.