Shares of Cedar Fair, the amusement-park chain that owns Cedar Point and Kings Island, briefly rose the most in almost a decade Wednesday on a report that Six Flags Entertainment approached the company about a takeover.

Six Flags is considering a cash-and-stock offer for Cedar Fair, according to Reuters. It's not certain an agreement will be reached, the news service reported.

A deal would unite two of the biggest thrill-ride operators, creating a chain of amusement and water parks that spans the U.S. A takeover would follow a June transaction to take the owner of Legoland's theme parks private for $6.1 billion. Analysts said at the time that the purchase could turn companies like Cedar Fair into more attractive takeover targets.

Cedar Fair shares rose as much as 11% on Wednesday to $64.86 — the biggest intraday rally since March 2010 — before settling down to a 3% gain. Six Flags slipped less than 1% to $51.22.

A merger would mark the return of the Six Flags brand to the Buckeye State. Geauga Lake amusement park owner Premier Parks acquired Six Flags in 1998 and went on to adopt that name in 2000 — the same year that it renamed the Aurora park Six Flags Ohio. The next year, after the company purchased neighboring SeaWorld Ohio, the combined park was renamed Six Flags Worlds of Adventure. In 2004, the complex was sold to Cedar Fair and operated as Geauga Lake and Wildwater Kingdom. Geauga Lake closed at the end of the 2007 season and Wildwater Kingdom followed suit in 2016.