Some characters can shrug off whatever their opponent throws at them. Except that doesn't stop their opponent from continuing to try. And wouldn't you know? The more the opponent keeps lashing out, the less effective the character's defense against it becomes, until eventually they go down as easily as anyone else. Looks like their immunity only lasted in the short run, but prolonged exposure still rendered them vulnerable.
Anime and Manga
- Pokémon: Episode Fire and Ice, during the battle between Ash's Kingler and Pete's Cloyster, Cloyster closes his shell, rendering Kingler's punches ineffective. Ash however orders Kingler to keep hitting Cloyster, and sure enough, after enough hits, it becomes too much for Cloyster and his shell cracks open.
- My Hero Academia: When the League of Villains storms the school, they unleash Noumu, a creature designed to counter All Might by being heavily attack absorbent. However, All Might deduces that Noumu being absorbent doesn't mean completely nullifying, and hammers blow after blow into him faster and more than Noumu can contain.
- Sonic X: In episode 73, Shadow storms through the heroes' spaceship to pursue Cosmo, handily disposing of any of their attempts to stop him. After a tense fight with Knuckles however, he stands the winner....only to faint in turn, finally succumbing to exhaustion. It's revealed he even had to take off his energy rings to finish Knuckles before he gets back up and continues unfettered. Interestingly the English edit omits this scene entirely, making Shadow seem genuinely unstoppable.
- Saint Seiya: in Poseidon Saga, the first Mariner Seiya has to fight is Hippocampus Baian, who's a Barrier Warrior that can deflects Seiya's attacks creating barriers with the air. Very confident of his powers, he can't believe that after many intents, his barriers are finally broken by Seiya, being soon defeated just as Seiya did in the past with Silver Saint Misty, who had a similar fighting style and was defeated by the same way Baian did.
- DC Comics:
- Kryptonite is highly lethal to Kryptonians, but has no immediate effect on humans. Thus, they can easily handle it without consequences. However, prolonged exposure to Kryptonite will eventually cause agressive forms of cancer in humans. Lex Luthor discovered this the hard way after years of wearing a kryptonite ring as a protection against Superman.
- Final Crisis: In The Flash tie-in "Rogues Revenge", after declining Libra's offer to join his army, he created his own version of the Rogues, who eventually battle the original ones without success. The most notable case in which this trope applies is Heat Wave against Burn, Libra's counterpart, which is also a pyromaniac, just like him. When the two fire their weapons at each other, Heat Wave barely sweats and notices to Burn his weapon isn't powerful enough and his suit also of poor quality. It ends with Burn burning to the death.
- The Tommyknockers: due to a metal plate in his skull, Jim Gardener is initially unaffected by the alien spaceship, while everyone else around him slowly starts to "become" (mutate into aliens). It also prevents his mind from being read when everyone else gains telepathic powers. But after several weeks of working day in, day out to dig up the ship, and thus being extremely close to the source, Gardener too starts to display the symptoms of "becoming" (like losing his teeth) and realizes it's getting more and more difficult for him to keep the telepaths out of his mind.
- Played for horror on the Stephen King short story "Night Surf": the teenager pack that is the protagonist of the story survived the rampage of a super-virus called "Captain Trips" and, in the face of the fact that the super-flu has a 100% infection and casualty rate, they only assume that they did so because they were immune. The final couple of paragraphs of the story has them discovering that "Captain Trips" has evolved and their immunity, if they ever really had one, is completely useless.
- Jessica Jones (2015) Plays with this trope. Since Jessica grew immune to his mind control powers, Kilgrave eventually tries to invoke this trope by giving himself a power boost in hopes that this will cancel out Jessica's immunity. Unfortunately for him, it fails. Jessica is still immune.
- Star Trek: Voyager: In the episode "Bliss" a telepathic nebula tries to lure the ship into itself so it can eat it. Seven of Nine believes herself to be immune to it because she is a former Borg drone with many cybernetic implants. However, she was only immune to the initial attack because she didn't have the desire to return to Earth that the rest of the crew shared. Once the nebula tried to fool her into thinking something had happened that she did want, i.e. that she had succeeded in escaping it, it turns out that she was as vulnerable as anyone else.
- In Legends of Tomorrow, Nate Heywood/Steel is a Chrome Champion who is Immune to Bullets, but even he has limits. In the episode "Freakshow", he is tied up and repeatedly shot at, which appears to strain him and by the end he's begging for it to be over.
- Batman: Arkham Knight: The Scarecrow has developed a partial immunity to his own fear toxin. Keyword "partial" as he can take one dose with no effects, a much larger dosage will cause him to hallucinate his worst fear (a demonic version of Batman) just like everyone else.
- Star Trek Online: Borg drones will adapt to incoming energy weapons fire after a few hits, but this only reduces incoming damage from that energy type. Even if you don't refrequence your weapons with a cheaply replicateable item, you can still Cherry Tap the drone to death.
- Codified by StarDestroyer.net. It is always regarded as possible to simply wear down an enemy with sustained fire; to say otherwise is called the "no limits fallacy".
- Justice League: Thanagarians are immune to J'onn's power. Until the situation is critical enough for him to try harder.
- BIONICLE: The Pit Mutagen is powerful substance that can mutate any being exposed to it, however organic creatures are affected by it so slowly that the effects are unnoticeable, while Brutaka's species have a slight resistance to the point of changing physical appearances slowly.