Once-ler and Vanellope have similar personalities, both of them being sassy, fun-loving, and rather stubborn. Both of them were also ridiculed by their families or societies to some degree, with one being called a glitch while the other was called a failure. At first, the Once-ler may find Vanellope annoying, much like Ralph did, but eventually, fans believe the two would become good friends.
As with Audler, Rapunzler, Annaler and other pairings, fans believe that Vanellope would also try to stop the Once-ler from chopping down the Truffula Forest, though whether or not she succeeds varies from story to story.
There are several instances where fans portray the two characters romantically, but it is more common to see them portrayed as best friends or as brother and sister.