Mewes v. State, 517 P.2d 487 (Wyo. 1973) concerned an appeal from a conviction for aggravated assault and battery with a deadly weapon. There, the victim Cooper began a bar fight and attacked Mewes. Cooper was stabbed, and Mewes ran from the bar. One witness saw Mewes stab Cooper in the back. Mewes contended that he had not stabbed Cooper or in any manner participated in the stabbing or even had a knife or instrument that could have inflicted Cooper's injuries. Mewes, 517 P.2d at 488. On appeal, Mewes claimed it was error for the trial court to fail to give a self-defense instruction. We decided that the obvious nature or quality of the plea of self-defense is that of justification or excuse for an otherwise unlawful homicide or assault and battery. Id. at 488-89. Because the defendant denied that he stabbed the victim at all, a jury would not have been able to somehow infer that he had stabbed the victim in self-defense. Id. at 489. "When a charge of this character is made and there is a denial of the stabbing, the only issue presented to the fact finder is whether defendant did in fact stab complainant." Id. at 490. The Court concluded that the trial court did not err in failing to give a self-defense instruction because it would have prejudiced Mewes and deprived him of his defense. Id.