Invincibility

Invincibility is the property of being totally resistant to all forms of harm. Because of this, the obvious problem with Invincibility is that it could very easily make a character who has the superpower overpowered. To counter this potential issue, Invincibility comes with many limits, with one being how incredibly rare it is. Invincibility is unlocked through any abilities, weapons, tools, or equips that make the user, holder, or wearer completely immune to incoming harm. In most franchises, it's only considered overpowered if protagonists have Invincibility while antagonists can much more commonly be seen with the superpower in their arsenal. There are antagonists who have some sort of Invincibility as their main ability, which forces the Good Guys to find out how to circumvent their foe's power.

Limitations

 * The user has a very short time to be invincible.
 * The user has a long cooldown time.
 * The user is only invincible to certain attacks.
 * The superpower is granted through usage of an item. Without that item, the user loses access to Invincibility.