A prosecution instruction pinpointing the defense theory, over the objection of the defense, is unduly argumentative, favors the prosecution by restricting the use of circumstantial evidence to raise a reasonable doubt, and violates the right to a jury trial, but it is nevertheless harmless beyond a reasonable doubt. The jury was instructed that, “[w]hen a defendant commits a robbery by displaying an object that looks like a gun, the object’s appearance and the defendant’s conduct and words in using it may constitute sufficient circumstantial evidence to support a finding that it was a firearm.” The challenged instruction was taken from Justice Scotland’s analysis of a sufficiency of the evidence claim in People v. Monjaras (2008) 164 Cal.App.4th 1432, 1436, which held the authenticity of the gun used in the commission of a crime must be left to the jury’s assessment of circumstantial evidence. The transmutation of the language into an instruction was not consistent with its original usage. The instruction did not direct a verdict, but it did impermissibly lighten the prosecution’s burden of proof. In such circumstances, the standard of Chapman v. California (1967) 386 U.S. 18, 24 applies.