Plain error affecting a substantial right can be considered by the court on motion for new trial, post-trial motion, or on appeal even if it was not brought to the trial court's attention.
Minn. R. Crim. P. 31.02
Comment-Rule 31
On appeal, the plain error doctrine applies to unobjected-to prosecutorial misconduct. The defendant bears the burden of showing that error occurred and that it was plain. Once the defendant has made that showing, the burden rests with the prosecutor to show that the error did not affect the defendant's substantial rights. See State v. Ramey, 721 N.W.2d 294, 299-300 (Minn. 2006).