A silent guardian, a watchful protector... a grammar vigilante.

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There's another caped superhero in town, and no, he doesn't fly or climb walls.

He's the "grammar vigilante," fighting for good punctuation in Bristol, navigating alone through the night to correct apostrophes on shop fronts.

His weapon of choice is an "apostrophiser," which he uses to reach the highest signs.

The "Banksy of punctuation," who uses stickers rather than paint, denies it's a crime to go around the city to improve standards:

"It's a crime to have apostrophes wrong in the first place," he told the BBC.

Just like with the Bat-signal, people are using hashtag #grammarvigilante to call him to fix crime punctuation in the city:

@BBC_HaveYourSay This sign in my town used to make me itch. Is the Grammar Vigilante recruiting? pic.twitter.com/q8ECssDjW3 — Katy Bovaird (@KatyBovaird) April 3, 2017

Grammar Vigilante, we need you here. pic.twitter.com/jDMDxNuRTi — Carl Rackman (@CarlRackman) April 3, 2017

However, any hero has a dark side.

Many people couldn't help but notice on Twitter that the "grammar vigilante" should be a "punctuation vigilante" instead:

The #grammarvigilante is actually a #punctuationvigilante - there's a difference. If you want to be a pedant, do it right. Er, correctly. — Nick Szczepanik (@NickSzczepanik) April 3, 2017

Hmm. Calls himself a grammar vigilante but all he talks about is apostrophes, which are nothing to do with grammar. https://t.co/U35RvApv3Q — Oliver Kamm (@OliverKamm) April 3, 2017

@DPJHodges As has been pointed out to me, he's clearly a punctuation vigilante, not a grammar vigilante. It amazes me how often people get this wrong. — Jon Wensley (@jonwensley) April 3, 2017

@jonwensley @DPJHodges Well said. The misuse of reflexive pronouns is more irritating to myself than missing apostrophes. — Jon Driscoll (@DriscollFC) April 3, 2017