A trademark is a trade name for a product (like Xerox for photocopy, Kleenex for bath tissue) Maybe STAR Labs or Lex Luthor trademarked Kryptonite for kryptonite? (okay, it's made a bad joke) dizzy

Big Apricot Superman Movieverse
The World of Lois & Clark
Richard White to Lois Lane: Lois, Superman is afraid of you. What chance has Clark Kent got? - After the Storm