Don Kirshner was music supervisor for the Monkees during their "Last Train to Clarksville" heyday. A dispute with the band over whether they should play their own instruments (he didn't think they should), and with Colgems Records over who should select the B-side to their latest single (he thought it should be him, not them) - left him without a job.
Kirshner bounced back by working with a band that couldn't possibly fight back - because they didn't exist in our plane of reality. The Archies were a cartoon, after all.
Despite not existing, the Archies managed to release a #1 record ("Sugar Sugar"), and Kirshner somehow managed to
travel through the cartoon universe to pay them a visit.