Sometimes the best offense is a good defense. This trope is about characters "attacking" by exposing themselves and their target to danger which they only expect themselves to survive.

This can range from the mundane (e.g., an amphibious character forcing their opponent onto land or drowning them) to the more fantastic (e.g., fireproof characters dragging their opponents into a burning building) and more abstract situations (e.g., stranding themselves in the desert when they have more experience surviving in it). It can also cover weaknesses that the target has which aren't shared by most people; what matters is that one character lacks the weakness and exposes them both to it (or they are exposed to it by the immune character's allies). It also counts if the character is only resistant rather than completely immune to whatever they're exposing themselves to (allowing them to claim Victory by Endurance).

This is one of the ways to use a Swiss-Army Superpower or to give a Technical Pacifist a victory. It can also show off an Adaptive Ability if it's used with something that the character was previously defeated with as well as being one of the many ways to use Geo Effects. If it's used against a protagonist, then expect a struggle to either escape in time or for them to end up stealing whatever was allowing their opponent to pull it off (e.g., stealing a mook's parachute after being pushed out of a plane). A monster with a Removed Achilles' Heel will likely use this on a less fortunate member of their own kind to show off their new lack-of-weakness. In many Platform Games, the player takes Collision Damage, while enemies don't, meaning they have but to walk into the Player Character to damage them.

It can also be used defensively, by entering an area that is safer for you than your opponent, daring them to Try and Follow at their own risk, or else let you escape.

Supertrope to:

• Drugged Lipstick (unless there's explicitly another reason the user isn't affected by the drug)
• Give Chase with Angry Natives (where the hazard is a third party).

Compare:

• Acquired Poison Immunity (you've made yourself resistant to a poison, so you can expose both of you to it)
• Friendly Fireproof (for when the hazard in question is your allies' attacks)
• Good Thing You Can Heal (since you can heal, you can exploit it by walking into/through dangers to gain an advantage)
• You Can't Kill What's Already Dead (undead can shrug off effects that the living can't).

Contrast:

• Briar Patching (when Alice tricks enemy Bob into doing something helpful to her)
• Immortal Life Is Cheap (you will be killed along with the target, but you can recover)
• Immunity Disability (where immunity to something can be "exploited" against said immune person)
• Revive Kills Zombie (where the same effect heals one type of character but kills another)
• Suicide Attack and Deliberate Injury Gambit (where the attacker is harmed)
• We Have Reserves (where the attacker's allies are harmed — but the attacker doesn't care)

Some versions of the Self-Poisoning Gambit rely on this. If the attacker's "unharmed" because they've already been harmed, this overlaps with Disability Immunity. See also Symmetric Effect, as this trope is one way to exploit mutually damaging variations.

Examples: