In the US, the Marathon branding was used for a 12” long caramel braid covered in chocolate. The marketing was that it was so big, it would take a long time and a lot of effort to finish (like running a marathon). If I recall correctly, the packaging even had a ruler printed on the back of the wrapper.
https://www.thedailymeal.com/1346025/why-marathon-mars-bars-discontinued-soon/
That my friend is a curly wurly https://snamix.com/chocolate/cadbury-curly-wurly