Gangs fight, tumble from scaffolding, swing across the stage acrobatically; youths in drag enact a Sinhala-language mini-farce, to roars of laughter.
A young gay man is hanged upside down by his legs and commits suicide by drinking poison, leaving the audience horrified.
There is a constant musical backdrop of choruses and sophisticated dancing. The show is so physical that some actors have suffered injuries.
This is Rag, Sri Lanka's first homegrown musical, which has just been playing in Colombo.
It depicts ragging, the often violent university initiation rituals common to several South Asian countries.
Lick toilet bowls
The show's creator, director, composer, choreographer and lead actor, Jehan Aloysius, 35, has been working on it well over a decade - but only now has the final version appeared.
He wanted to depict resistance to what he calls the "absolute horror" of ragging.
Just before he went to Colombo University in 1997, two young men had died of ragging on Sri Lankan campuses involving enforced push-ups and alcohol consumption, internal bleeding and kidney failure.
Earlier a girl was paralysed when she fell off a balcony while fleeing raggers: She later committed suicide.
"When I got my acceptance letter, rather than elation I felt horrified and I hid the letter from my mother," Mr Aloysius told the BBC. "She found it four months later."
When he started his higher studies he considered feigning illness to avoid ragging, which is inflicted on "freshers" by senior students.
In the event he was spared the worst practices but says some contemporaries had to lick toilet bowls, eat food mixed with cockroaches or strip naked. Those who stayed in hostels had it far worse, he says.
Yasmin, a Muslim woman who studied at Sri Jayawardenepura near Colombo in the 1990s, believes Jehan Aloysius "presented the anti-ragging message well" by leaving the audience shocked.
Her own ragging lasted seven months. Some acts were harmless but others were not.
'Blood, sweat and tears'
"Girls had to run around on the basketball court in the hot sun," she said. "Some of the physical ragging was so intense that some girls later developed complications in their wombs."
In "bucketing", the final ragging ritual for full initiation, she had to crawl through a makeshift tunnel before being soaked with a bucketload of liquid. It was not water.
"They collected the outflow from drains, sinks, maybe sewers, for months. They put worms in it and let it ferment."
Mr Aloysius cast Rag with people new to the stage who could, however, sing well.
He auditioned 250 young people for 12 lead roles. During the trials he asked students about ragging at their colleges.
"They'd freeze, they aren't allowed to talk about it," he said. "After six months of "blood, sweat and tears [rehearsals] they shone."
Mr Aloysius plays the lead character, Joseph, who starts a non-violent anti-ragging movement but conflicts with Rukmal who says it must be violently resisted.
There are autobiographical and biographical elements.
One leading female character, Natasha, is loosely based on Avanti Perera, a contemporary of Mr Aloysius and the show's main instrumental musician.
Sociology of ragging
In the play as in reality, ragging involves dictating a dress code.
"I went to the campus in a luminous green miniskirt and rainbow top. One English lecturer said, Here comes trouble," Ms Perera recalled. Senior students threatened to strip her but that was as bad as it got.
Rag the musical depict excesses like that experienced by Avanti.
Departing from its biographical model, the character Natasha is raped and two youths, including the lead, eventually die - one in a fight.
A former victim of ragging who reviewed the show, Kumar de Silva, felt the rape scene was excessive but others point to the power of the violent material.
There is a sociology of ragging.
Those associated with the show told the BBC that it has often been directed especially against students from the English-speaking elite.
Many of the anti-ragging students in the musical are from the English faculty.
And in recent Sri Lankan history it has been associated with the JVP, a radical leftist party that is highly influential on campuses and which waged a guerrilla insurrection of shocking violence in the late 1980s.
Milder ragging has its supporters as an equalising ritual which seems to transcend ethnic divisions.
"We were ragged by the seniors. I wanted to hit them at the time. But today they are very close friends of mine," says Arshad, a former student. "It created a good bond. But it should have limits."
He and his batch-mates had to write and read out sexual stories, dance or pretend to propose to girls. For him it lasted six weeks and got no worse.
Jehan Aloysius, however, is still haunted by hearing of a ragging-related death in 2002 after he wrote the show's first draft.
The victim was repeatedly hit while unconscious.
He hopes the show will persuade the audience that the practice is more than just bullying.
Ragging has been illegal since 1998 but there have been few or no prosecutions.
"If there's a message I want to bring out, it's that campuses and educational institutions should be spaces of non-violence," he says.
The standing ovations for the show's run in Colombo suggest its message is getting through.