One power that appears in a good many video games is temporary invulnerability. I don't know how this idea started, but it's been around since the early days of video games. Pac-Man has the pills that will allow him to devour the ghosts, although they do come back. It's typical in early video games for there to be no defined end point, but the fact that Pac-Man can only defeat his enemies for very brief periods of time could be seen as rather depressing. When you play Pac-Man, you KNOW you're going to die sooner or later. Anyway, Donkey Kong gives Mario a hammer that he can use to smash barrels automatically, but it's the Starman that became the typical invincibility-granting item in most Mario games. Not only can Mario's enemies not harm him when under the effects of a Starman, but his mere touch will kill them. Other games use that same basic idea, with a certain item temporarily transforming the hero into an unstoppable killing machine.
There are other variations on the invulnerability idea, however. I believe both Wizards & Warriors and A Link to the Past have items that make the bearer invisible, which makes the enemies unable to harm you because they can't see you. I'm not really sure why that would matter if you're running right into them, but I'm also not sure how to better represent invisibility in a video game. The Dragon Quest series has invisibility herbs that let you sneak into some place, but RPGs are a different story.