Raider was a brand of chocolate bar by Mars distributed in Northern Europe. It was introduced in West Germany and Austria in 1976 and sold under that name until 1991, when it was renamed Twix in line with the brand name used elsewhere in the world.
Mads Nielsen loved the chocolate. Jana Nielsen found a Raider wrapper in the forest in 2019 and suspected it had something to do with Mads' disappearance. Helge Doppler also enjoyed it, and ate a chocolate bar earlier on the same day he kidnapped Mads.
Young Hannah is seen eating it while chatting with Mikkel Nielson in the hospital.
Raider (pronunciation like rider in German) was a top-selling chocolate bar in Germany. The decision to rename Raider to Twix in 1991 was therefore accompanied by a massive and memorable national advertising campaign featuring the slogan "Raider heißt jetzt Twix—sonst ändert sich nix," which can be loosely translated as "Raider is now Twix—nothing else has changed."
While this campaign took place years after the 1986–87 events depicted in Dark, it was ubiquitous to the point that "Raider heißt jetzt Twix" entered German slang. In modern use, it tends to be a critical or disparagin remark about something that has only changed in name, not substance, as with some public policy measures or political organizations.
This sense resonates with the recurring themes of constancy amidst name changes and time travel in Dark. In every cycle, children disappear, and the bodies of other children are found, though the identities of the children change. Michael Kahnwald cannot escape that he is truly Mikkel Nielsen. And Aleksander Tiedemann has several past identities he cannot escape from. And even Benni, undergoing a transformation to Bernadette, remains Torben Wöller's sibling and apparent co-conspirator.