Warning! Spoilers for Star Wars: Darth Vader #25 below.
Underestimating Darth Vader nearly almost always ends up being a death wish to whoever in the Star Wars Universe thinks they have the upper hand on the powerful Sith Lord. This was never more apparent than in the comics when the scientist Cyclo scoffed at Vader for a Jedi mind trick he thought wouldn't work against him when in reality, it was his scariest and darkest move ever.
In Star Wars: Darth Vader #25, the final issue of the series by Kieron Gillen, Salvador Larocca, Edgar Delgado, and Joe Caramagna, Vader tracks down Cylo, a scientist who betrayed the Empire and offered Vader to the Rebels. Cylo first worked for the Empire to create clones of himself who could be used by the Empire - while the original version could switch easily between bodies. Emperor Palpatine requested the Sith Lord kill Cylo for good for his betrayal and after making his way through his army of clones on his sentient whale-ship, Vader committed one of his greatest atrocities to date.
Related: Darth Vader Discovered the Secret Prisoner of Exegol Before His Death
Upon encountering Darth Vader on his ship, Cylo tells him his clones were great achievements and that he effectively made himself immortal by transcending the laws of nature "and the trap of the Force." Vader doesn't respond to Cylo's ego, telling him he will turn him into ash and commands "you will fly into the sun." When Cyclo tells him his mind is protected from Jedi mind tricks, Vader reveals he wasn't speaking to Cylo, instead, he was commanding his sentient whale-ship.
Cylo realizes what Vader has done and immediately scrambles. He's in shock and can't believe he lost control of his machine, calling himself "the master" as the whale-ship heads directly towards a nearby sun. Cylo can only look out the window in horror as his ship drives directly into the sun under the orders of Vader. His claim to being immortal is immediately proven false, as Cylo burns up in the ensuing crash.
Darth Vader has committed some incredibly dark acts under the stewardship of Emperor Palpatine, but his greatest Jedi mind trick ever is when he convinced Cylo's ship to steer itself into sudden death. He amazingly used his powers to Force a sentient ship to commit suicide by driving directly in the sun. Cylo was helpless, as his last words emphasized how shocked he was before dying, stating the scenario was "impossible" before burning to death. Among Darth Vader's scariest moves, few top the incredibly dark moment while showing how powerful the Star Wars villain truly was.