Reading a review for the new Fast and Furious film I came across the (American) idiom "jumping the shark".
Jumping the shark is an idiom used to describe the moment of a misguided attempt at generating new publicity for something once, but no longer, widely popular; the attempt serves instead to highlight the irrelevance of what it intends to promote. This is especially applicable to television series or other entertainment outlets. https://en.wikipedia.org/wiki/Jumping_the_shark
I was curious if there is an idiomatic way to convey "jumping the shark" as below
“This is Trump’s jump the shark moment,” John Feehery, a former key aide to Republican congressional leaders, told the Daily News. “It’s all downhill from here.”