Tobari: Sorry, Aizawa. I can punch him. [punches Fuuma]
Our hero is in a duel with a crafty Shapeshifter villain. It looks like the shapeshifter is going to lose, until they bust out the most underhanded trick of all — suddenly impersonating one of the hero's loved ones or True Companions, trying to cause them to lose their will to fight.
Usually, the hero ends up struggling to find the willpower to continue beating up someone who looks just like their loved ones. Bonus points if the form the shape shifter takes on is that of a dead friend or family member for extra guilt; especially if it is one whose death the hero blame themselves for. There are also bonus points if the shapeshifter was the one who killed the dead friend or family member and is enhancing the emotional kick of their evil gloating. Some examples may finish off the illusion by talking to the hero "in character".
If the protagonist is an Anti-Hero, there's the possibility that they won't care at all about what face they are kicking in as long as they know whose face it actually is - the bad guy's.
There's also an increasingly common subversion: because of personal issues between the hero and the character the shape shifter takes the form of, the hero actually becomes more willing to attack. Also, all the shape shifter may do is succeed in pushing the Relative Button and making things even worse for the shifter.
Also see Critical Hesitation Blunder (when the hero hesitates and it costs him), Doppelgänger Gets Same Sentiment (the reason this sometimes works), Shapeshifter Swan Song and Treacherous Spirit Chase. Contrast Shapeshifting Seducer.
- In Nodwick, the party encounters an undead monstrosity that uses magic to make whoever is looking at it see a dead mentor or parental figure they would trust implicitly (Nodwick sees his former guildmaster, Arthax sees the man who trained him to be a wizard, Piffany sees the head priest who raised her, and Rowan sees her adventurer father). All of them can only stare dead-eyed at it and mumble "I thought you were dead". Fortunately, while the magic also affected Orville, his species of dragon instinctively try to fight and kill their own parents for dominance.
- Inverted in Dreamscape. Assassin Tommy Ray murdered his father as a teenager. While fighting him in a dream, the heroic Alex distracts him by changing his appearance to that of the father and asking Tommy Ray why he killed him.
- In The Exorcist, the demon takes on the voice of Father Karras' recently deceased elderly mother.
- In Event Horizon, the title ship has taken over Dr. Weir. In an effort to get to Captain Miller, Weir takes the form of a flaming Edward Corrick, the man in Miller's back story whom he had to leave behind in his greatest failure. Miller doesn't buy the attempt to guilt-trip him for a minute though: "No. You're not Edward Corrick. I watched him die."
- In Hansel & Gretel: Witch Hunters, when Hansel is beating up the evil witch Muriel, she takes on her beautiful form (Famke Janssen) and begs for mercy. Hansel says, "Nice try," and continues the attack.
- In Mortal Kombat: The Movie, the villain Shang Tsung tries to pull this gambit with Liu Kang by assuming the form of his dead brother Chan, whom Shang Tsung had killed at the start of the movie. It doesn't work.
- The monster in Phantoms turns itself into a little boy who looks like the kid Ben Affleck's character accidentally killed in his former life in the FBI.
- In Pokémon Detective Pikachu, a Ditto transforms into Tim's crush Lucy while he's fighting it. Tim starts saying that he has no problem hitting it regardless, but it takes the opportunity to knock him off his feet while he's talking.
- In the Spiderwick books and The Film of the Book, Mulgarath attempts to do this to the main character by transforming into his dad. Much like in the FMA example, the main character has Parental Issues and this ends up being a bad choice.
- The T-1000 from Terminator 2: Judgment Day made use of this trope, shapeshifting into Sarah Connor in an attempt to lure and terminate her son John. The attempt fails when the real Sarah appears behind the T-1000, and John trusts her characteristic approach ("Get out of the way, John") over the duplicate's attitude of slumped defeat. The film's special edition, disappointingly, replaces this subtle indicator with an obvious shapeshifting flaw (warped and misshapen feet).
- In Wrath of the Titans, Perseus fights and defeats a minotaur. As he's about to finish it off, the minotaur suddenly starts talking in his son's voice, begging his "father" not to hurt him. Perseus kills it anyway.
- X-Men Film Series:
- Mystique tries this on her captors in X-Men: The Last Stand. She transforms into the President and threatens to have them all court martialed if they do not release her, and then a little girl who begs and cries to be let out. She finally turns mockingly back into herself when one of the guards threatens to empty a can of pepper spray in her face if she doesn't knock it off.
- In the second movie, X2: X-Men United, while in an Enemy Mine situation with the X-Men, she tries to seduce Logan as Jean, Rogue, and Storm. He gets wise when he sees the scars he left on her belly from the first movie.
- The special ability of Kyton devils in Dungeons & Dragons. They appear like humans wrapped in chains, but during a fight they reveal their face, which imitates someone their attacker knows.
- In Monte Cook's World of Darkness, Demons can learn the ability to read a victim's most emotionally compromising memories and reflexively shapeshift into the people associated with them. With the demon's supernatural power, the assumed form lets them deliver an Emotion Bomb or even implant subliminal instructions in the victim.
- In DEATH BATTLE!, when Obi-Wan finds himself trapped in a genjutsu by Kakashi, who should appear but Darth Vader himself, wreathed in shadows and with glowing red eyes.
- In the finale of RWBY Volume 7, Team JNPR faces off against Neo, a Master of Illusion who at one point uses her powers to disguise herself as Nora in order to steal the Relic of Knowledge off Oscar when he lets his guard down. As she escapes, Ren tries to strike her down, only for Neo to switch her Technicolor Eyes to Nora's light blue and flash Ren a look of fear. Ren and Nora are close Childhood Friends who also received a Relationship Upgrade a few episodes before this, so it's not surprising when Ren freezes up with a horrified expression, giving Neo enough time to take him down and easily retreat. While it's clear it's only a Critical Hesitation Blunder on Ren's part, apparently the mere notion of hurting Nora is enough to cause him to cry.
- In Archipelago, Face-Changer Han finds himself backed into a corner by Lucinda, and attempts this trope multiple times to save himself. He shifts into Knull (their Token Good Teammate), Miss Tabitha (Lucinda's former mentor), and Corveau (the man who broke her heart, causing her Start of Darkness). It doesn't take, and she runs him through. At her behest, he shows her (but not the reader) his true form before their mutual Disney Villain Death.
- In Drowtales, Khaless does this to Lulianne using the face of her niece Sael, who Khaless may have killed and/or absorbed.
- Nodwick: An evil cleric creates Masques, undead monsters that appear as a person Back from the Dead to whoever sees them, allowing them to approach their target unhindered. It would have worked, except one of the victims was a dragon, who have... very territorial instincts where it comes to their parents. It therefore torched the dead, breaking the spell.
- A downplayed example appeared in everybody's favorite Trope Overdosed work, The Order of the Stick, when Elan's Evil Twin, Nale, faces off against Roy. If he was hoping that Roy would be reluctant to attack someone who looks identical to one of his party-members, he was DEAD WRONG.
Roy: I've been suppressing the urge to beat the crap out of someone who looks EXACTLY like you for a long, long time.
- In Wilde Life, Clifford first meets Raven when the latter looks like a little kid, though he quickly learns that Raven knows humanshifting and likely took that form to seem more innocent than he really is. At one point Cliff is about to attack Raven when he's in his teenage form, only for him to quickly switch back to being a kid. Clifford pulls back on instinct and, combined with his general stress and drunkenness at the time, winds up throwing up.
- Played with in the first episode of Gary and his demons: in the Dramatic Chase Opening Gary maims an orphan he thinks is a shapeshifting demon in disguise, though in Gary's defense, he makes a very good argument why and manages to counter all the arguments the orphan makes about not being a demon. Later, the same demon plays it straight by disguising itself as the now crippled orphan.
- Mocked in Seanbaby's Super Quiz.
Question 13: Shape Changers You're in a fight against a group of super villains, and one of them is a shape-changer. Suddenly, your dead girlfriend shows up in her underwear. Do you: A: Ignore her. It's possible that your girlfriend climbed out of her grave, changed into her panties, and got on a plane to see you during a fight, but it's probably the shape-changer, genius.