Atom Smasher
In the 925th Universe, the Atom Smasher was a superweapon with which the Super Besties Justice Squad were able to threaten the otherwise-nigh-omnipotent Stardust the Super-Wizard, who believed it had the power to “neutralise” him. The Super Besties used it to bully Stardust into un-deleting France in 2022. (PROSE: A Series of Queer Events (2024 reedit))
Behind the scenes
The Atom-Smasher (originally spelled with a hyphen) was a device which briefly appeared in the first-ever, public-domain Stardust the Super-Wizard comic. There, it was shown to be the strongest secret weapon in the possession of “the secret army of spies and terrorists” against which Stardust was waging a one-man war.
Notably, the story's events soon showed that as far as this original Fletcher Hanks continuity was concerned, the Smasher was still not enough to stand up to Stardust, who used his “boomerang ray” as soon as he felt the Atom-Smasher's “long-range automatic finder” being aimed at him, and used it to reflect the Smasher's power back on itself, destroying it.
Though it is still conceivable to read the story such that a direct hit from the Atom-Smasher could have destroyed destroyed Stardust if he hadn't been forewarned, it is not clear how even this would enable the Super Besties Justice Squad to use it as a deterrent against him, as such a use would lose them the element of surprise and give Stardust ample time to equip himself with his boomerang ray. It is possible that the Super Besties duplicated Stardust's boomerang-ray technology for the Smasher, or otherwise protected it against Stardust's power.