The IT: Welcome to Derry opening credits have slowly been getting even more horrifying, and you probably didn't even notice

IT: Welcome to Derry aired its most terrifying episode yet with episode 5 – but there's one hidden, eerie detail that's been getting steadily creepier involving the opening credits, and you probably haven't even noticed.

The opening credits are already suitably scary, set to the song "A Smile and a Ribbon" by Patience & Prudence. What looks like suburban bliss is slowly revealed to have a darker edge: we see a lobotomy in Juniper Hill Asylum, a smiling teacher showing a nuclear blast to a room full of cowering kids, and glowing yellow eyes from inside the house on Neibolt Street.

But, as it turns out, the credits have been getting even spookier week by week. As spotted by a sharp-eared fan on Twitter, the credits have slowly been introducing ambient noise in the background, so the opening has been getting more and more unnerving. Check out a comparison below.

"That's all Andy," confirmed Welcome to Derry's editor, Matthew V. Colonna, on Twitter, referring to series creator Andy Muschietti.

The change has been audible from episode 3, too, as another fan noticed earlier in the show's run:

IT: Welcome to Derry episode 5 saw the highly anticipated return of Bill Skarsgård's Pennywise, who terrorized the kiddos in the sewers – but was stopped from snacking on Lily by the dropped dagger...

It certainly looks like the kids might have a chance at stopping the clown from getting them, then, but one fan theory around Marge suggests Rich might be done for.

You can keep up to date with the show with our guide to the IT: Welcome to Derry release schedule, or fill out your watchlist with the best shows on HBO Max and all the upcoming Stephen King movies and TV shows.