Supreme Court Justice Elena Kagan Geeks Out on Spider-Man

— -- Elena Kagan’s spidey senses are tingling.

The Supreme Court justice penned an opinion released today that ruled against a toymaker attempting to collect royalties on the Web blaster, a gadget that shoots silly string from a glove, Spider-Man style.

In the 6-3 decision, the court ruled that Marvel Entertainment -- which purchased the toy's patent in 2001 for $516,000 plus 3 percent of net sales -- can continue to sell the contraption without paying additional royalties to the inventor, Stephen Kimble, because the patent is expired.

Justice Kagan, 55 -- “an avid fan of comic-book-based action films,” according to the "Supreme Court Review" -- had a little fun with the references to Spider-Man's alter ego, Peter Parker.

Spider-Man, Spider-Man

“The parties sent no end date for royalties,” Kagan wrote, “apparently contemplating that they would continue for as long as kids want to imitate Spider-Man (by doing whatever a spider can).”

Kagan’s parenthetical is a throwback to the 1967 TV theme song: "Spider-Man, Spider-Man / Does whatever a spider can."

Was Kagan humming in her chambers? We’d like to think so.

With Great Power ...

In another parenthetical citation, Kagan quotes Peter Parker’s Uncle Ben: “[I]n this world, with great power there must also come -- great responsibility.”

For Spider-Man, that may mean vanquishing a supervillain.

For the court, that means declining to overrule a long-standing precedent that patent holders aren’t entitled to royalties after the patent expires.

A ‘Web of Precedents’

This one’s a bit more subtle.

“The decision’s close relation to a whole web of precedents means that reversing it could threaten others,” Kagan writes.

... Web -- get it?

Superpower Patents

“Patents endow their holders with certain superpowers, but only for a limited time,” Kagan wrote.

And once the "superpower" expires, Marvel Entertainment can stop paying royalties.

Marvel Entertainment is a division of The Walt Disney Company, which also owns ABC News.

ABC News' Jill Ornitz contributed to this report.