10 Amazing Behind-The-Scenes Secrets From Star Trek: The Next Generation
9. Worf Loses His Head
The varying nature of Klingon cranial ridges has long been a bone of contention for Star Trek fans. They're entirely absent from the original series, suddenly introduced in The Motion Picture, inconsistently enforced across the 90s, and then entirely reinvented for Star Trek: Discovery. Even Worf's have magically changed over the years.
His original head in the first season of the Next Generation looks distinctly different from that worn in season two onwards, and the show didn't think to offer us a cursory explanation as to why that might have changed.
It could be a natural part of the Klingon development in adulthood, it could be a situational thing from living on a starship, but whatever they went with it likely would have been better than the actual reason why it was changed. Michael Dorn's original prosthetic head was, between the first two seasons, stolen.
Precisely who stole it (and why) was never discovered by the production staff at Paramount, although one theory does suggest that members of the cast took several souvenirs assuming they wouldn't be renewed. Whatever the reason, it left them needing a new head and they took the opportunity to improve on the look.