During peak Beatlemania, circa 1964, screaming, sobbing fans were the worst of it. Today we have BTS mania, inspired by a K-pop band that breaks the internet — and world records — with infectious ear candy and intricate choreography.

But beware jumping on the BTS bandwagon; the group’s toxic fan “A.R.M.Y.” might wage war on you.

Oh, my, my, my. Let me explain.

BTS, the seven-member South Korean boy band whose acronymic name translates to “Bulletproof Boy Scouts,” has risen to massive global fame since 2013, garnering well over a half-billion YouTube views. In April, the buzz was record-breaking: BTS became the first group since The Beatles to nab three chart-topping Billboard albums in one year with the release of “Map of the Soul: Persona.”

It’s no surprise their reach has spread to New York City — young fans camped out for more than a week along Fifth Avenue to get first-come, first-served tickets to a free Central Park concert broadcast Wednesday on “Good Morning America.” Next up: The “Boy With Luv” hitmakers headline arena shows Saturday and Sunday at New Jersey’s MetLife Stadium, a venue with the capacity for 82,500 fans per night.

I’ll pass. Already had quite enough of that self-proclaimed A.R.M.Y. (Adorable Representatives M.C for Youth) this week, thank you.

A real — and disturbing — fan subculture is festering on Twitter. After attending a taping of “The Late Show with Stephen Colbert” Wednesday — when BTS was the musical guest riffing on The Fab Four’s iconic US debut in the same studio back in ’64 — I experienced their tactics first-hand.

First, I must admit I had never listened to BTS before attending the taping with five friends who are fans. I went for the experience, as well as the bragging rights to say I saw a world-famous act — which boasts 17.9 million Instagram followers — perform in an intimate space.

“NO BIG DEAL WE JUST SAW BTS AT THE LATE SHOW WITH STEPHEN COLBERT,” I tweeted after leaving the historic Ed Sullivan Theater in Midtown, along with a photo of me and my mates.

The “likes” quickly poured in, primarily from Asia. In under an hour, the tweet had more than 100 likes, prompting a bit of shock. Soon after, it rose to 300.

“GUYS I’M GOING VIRAL,” I tweeted, tongue in cheek.

“It’s gross that you’d use ’em as clout,” one user named @astrophilicdoll responded.

“The way you [retweeted] your own tweet … embarrassing,” @dvdtae chimed in.

“What [a] joke using BTS to be viral,” tweeted @hhttagustd with a photo of a man giving a judgmental stare.

Confused, and under the impression they didn’t understand my tone, I joked along, responding either “[you] mad?” or “I don’t think you get my joke.”

“I’m not mad, just disgusted,” @astrophilicdoll replied.

The negativity was quick and constant, but the reasoning for it soon became clear. A separate user, @syumoni_, told me the fan community had been dealing with “(old) white men” exploiting BTS in their tweets to get likes and follows, only to make fun of them. For instance, screenshots showed a verified user named @UncleChaps reply to a man’s tweet linking to a video of the band’s “GMA” performance.

“[This] is the thirstiest tweet for retweets I’ve ever seen and I love you for it,” @UncleChaps wrote. “And it’s working. Lights Camera Asian Market.”

Another refresh brought even more replies from BTS fan Twitter accounts, it was recommended that I add to my initial tweet, saying I wasn’t looking for fake Twitter impressions, which I did. But not everyone was convinced.

“It’s sad when someone goes and tweets about appreciating a show just to go and tweet about the clout they are getting from it,” @astrophilicdoll — my toughest critic — later posted. “Very sad. Very disgusting.”

At that point, the vitriol eased up. But others have had it much worse.

According to a Pop Dust post from March, some fans have cyber-bullied black BTS fans with racist taunts. One fan said they’d been called the N-word and was told to pick cotton.

“You’re a f–ing black monkey,” wrote another. “No one gives a f–k about you guys in this fandom.”

It’s frankly disgusting that bitter trolls have resorted to these methods to disagree with others. But it’s also sad that BTS has spawned a juvenile fandom that’s over-obsessed with a band. In addition to the hate, my tweet has reached nearly 2,000 likes, the majority coming from dedicated fan accounts operated by people who seem to have nothing better to do than spend their days on Twitter obsessively tracking the group’s digital trail.

It’s a wild world that’s not worth dipping your toes into.

If you plan on attending this weekend’s shows — and subsequently sharing your impressions on social media — I suggest you think twice.