Ska concerts are a phenomenon unlike any other. And, because ska is best described as dance-punk with a brass section, it’s no surprise. Nowhere else is there such a strange cross-section of angsty teenagers with middle-aged men who have large and unruly beards.

An even stranger phenomenon is the fact that all faces were plastered with a wide smile, and they had their hands raised high in the air as they sang along in perfect harmony.

Nowhere are all of these elements more prevalent than at a Reel Big Fish concert. The boisterous, crass, explosive ska kings of the ‘90s played at Royale on Friday, where they proved to be one of the most exciting, spontaneous and crowd-pleasing acts — even 20 years after their peak.

RBF’s “Don’t Stop Skankin’ Tour” — aptly named for ska’s trademark leg-kicking, arm-swinging dance — began with relatively tame opening bands Beebs and Her Money Makers followed by Beautiful Bodies.

However the show really began with reunited ska legends Five Iron Frenzy who harkened back to ska’s glory days with upbeat hits such as “Oh Canada,” to which the crowd responded with shaking and synchronized bouncing.

But the somewhat antsy crowd became frantic when the final lights dimmed, and the legendary Reel Big Fish took the stage.

Immediately after beginning with their ironic “Everything Sucks,” the crowd opened an enormous pit and, without warning, audience members dashed madly towards the middle of the circle.

Soon, the entire crowd joined in on the legendary “skanking” circle, a term used to describe the frenzied dance often found at ska shows.

The crowd kept dancing joyously, even to newer songs like “Everyone is an A**hole” and the eponymous “Don’t Stop Skanking” until the sudden collapse of the drum kit momentarily stopped the show.

By the end of the ordeal, the stage was littered with downed mics and tangled wires. The crowd had now stopped moving, and a look of genuine fear had spread across nearly everyone’s face. But what could have been an evening-ending mishap soon turned into a momentum maker, as RBF rewarded the audience’s patience with a medley of their most famous hits, starting with “Good Thing” and “Suburban Rhythm.”

Each time the band played another subsequent hit, the audience became livelier, until the crowd turned insane. Water bottles and cups of beer began flying everywhere, and it was unclear whether clothes were wet with sweat or alcohol.

The band deviated from their established set-list and instead went into a hit parade. The resounding cheers of the audience when the opening notes to the band’s number-one hit, “Sell Out,” were unmatched. It was a moment of pure, communal ecstasy.

It is important to remember that good crowds can make or break a ska show. If the crowd had been sluggish, the concert as a whole would have been dull.

Though the band’s prowess encourages an energetic crowd, it is ultimately up to the crowd itself to create a fun environment. Luckily, the crowd at Royale was enthusiastically dancing, screaming and laughing the entire time. Even in the pit, the good-natured crowd stopped to help a fallen comrade that had slipped on the slimy floor. The good vibes of the band were accentuated tenfold by the crowd.

As the show’s finale neared, the band began teasing their smash hit “Beer,” while accentuating a bit of their trademark humor.

“We’re going to play a song about our favorite beverage,” excitedly yelled frontman Aaron Barrett. The band then played a multitude of songs about a variety of different alcholic drinks, including “Red Red Wine,” “Piña Colada” and “Tequila.”

With each subsequent song, the crowd’s anticipation grew, until finally, the opening notes of “Beer” rang out over the crowd.

The ecstatic audience opened a skanking pit that stretched to the bar all the way at the back of the venue. The communal singing, the band’s obvious enjoyment, and the insanity of the pit made it a truly unforgettable moment.

The band left the stage to unstoppable cheering before returning several minutes later for an encore performance with their own rendition of A-ha’s “Take On Me.” After the thundering applause, the band walked off and the crowd began to disperse. Everyone was drenched in a mixture of sweat and spilled beverages and, although it sounds gross, it became another unifying element of the fantastic show.

With their hour-and-40-minute set, RBF whipped the crowd into a wild frenzy. A perfect amalgamation of funky music and a riotous crowd, this was not only one of the most enjoyable concerts of the fall — it was arguably a highlight of Boston’s entire music scene.