Gibson Guitar has filed a lawsuit against Activision, claiming the Guitar Hero games infringe one of the company's patents.
According to Reuters, Gibson has a 1999 patent for technology used to simulate a musical performance. It sent a letter explaining this to Activision in January.
"Based on our preliminary analysis, the Guitar Hero software (including any expansion packs) and the guitar controller provided by Activision being used as a musical instrument (packaged with the software or sold standalone) are covered by the ... patent," the letter read.
"Gibson requests that Activision obtain a licence under Gibson's... Patent or halt sales of any version of the Guitar Hero game software."
It's all a bit odd as the two companies have previously been big chums; Activision is licensed to model the Guitar Hero controllers on Gibson guitars and their likenesses appear in the games.
"Gibson is a good partner, and we have a great deal of respect for them," said Activision general counsel George Rose.
"We disagree with the applicability of their patent and would like a legal determination on this."
In other words, Activision has gone and filed its own suit - asking the court to declare Gibson's patent invalid, and bar it from seeking damages. Activision claims Gibson granted an "implied licence" by waiting three years to make its claim.
This isn't the only legal tangle the publisher is caught up in; Guitar Hero creator Harmonix is claiming its own royalties for the third instalment in the series.
Still, there's probably enough gold to give everyone a share and still have change for chips. More than 14 million Guitar Hero games have been sold in North America alone, and the game has raked in more than USD 1 billion since its 2005 debut.