Sonic Ceremony: How to Prepare for itchy-O’s Hallowmass

The season of sacred chaos is upon us. And to celebrate, Denver-based collective itchy-O is hosting its annual Hallowmass this weekend.

The multi-day ritual begins on Halloween night and continues through All Hallows’ Eve, Saturday, November 1, at Summit. The Austin, Texas, group SOUNDCULT — a collaborative project featuring Thor Harris (Swans), Leila Henley (Invincible Czars) and Lyman Hardy (Total Unicorn) — is also participating in the ceremony.

This is the eleventh year that the anonymous, sixty-member musical conglomerate known as itchy-O will be organizing Hallowmass. Within the group’s archaic lore and ceremonial rites, this year’s edition focuses on a very specific element that exists only in its carefully curated universe.

“Each year, Hallowmass focuses on one aspect of itchy-O’s Triad of Impermanence according to the group’s Exocosmic Narrative — Mayat Ōm honors the departed, Mayat Öd confronts the impermanence of the physical and (Ō) Expurgo! initiates the release of outmoded attachments,” says the anonymous leader of the group.

So this is no ordinary “concert,” but itchy-O has been anything but ordinary since manifesting itself among the city’s underground in 2009. The ensemble shares one singular voice, as seen by the anomalous answers, and has built a mythos filled with ancient knowledge and symbolic wisdom. Everything is interconnected and equally important.

“The 2025 rite centers fully on Mayat Öd, asking participants to consider what has grown brittle: roles that no longer fit, systems that have dissolved, and bodies or places we once depended on,” the leader explains. “The ritual invites symbolic offerings and active participation from all who enter.”

In order to prepare, interested parties may join the group’s Patreon, where the Hallowmass 2025: The Mayat Öd Resonant Primer has been posted, along with Lovecraftian-looking materials and shamanistic sound clips. Itchy-O encourages guests to arrive early in “ritual attire” and bring “symbolic offerings.”

“At the heart of the event is the Mayat Öd Altar, a sound-reactive structure composed of salvaged memory and material debris,” says the leader. “Guests are encouraged to bring physical objects representing attachments they are ready to release. These offerings will be ritually installed and transformed over the course of both nights.”

Each celebrant will also receive a Mandorlah — “a ceremonial headpiece symbolizing impermanence and transformation,” according to the Resonant Primer.

“You may inscribe it with words or symbols of what you’re releasing,” the leader explains.

Then on Sunday, November 2, a burn will take place at Johnson-Habitat Park “as shadow overtakes the land,” which is how itchy-O describes dusk. At that time, the offerings and Mandorlahs will be turned to ash.

“We’ll carry it to the flame together,” the leader promises. “No stage. No spectacle. Only release.”

Do not be intimidated, but embrace the ceremonial rites that are inherent to itchy-O, all the “mysterious order or paracosm,” as the collective calls it. For the curious, last year, Westword music editor Emily Ferguson was willingly “kidnapped” by the veiled practitioners in order to get a behind-the-scenes look at what goes into crafting Hallowmass. If you’re prone to falling down rabbit holes, it’s more than worth the read.

The hypnotic music itchy-O is known for, which is the amorphous core of all of this, is primal yet futuristic. It seems rooted in thousands of years of manmade melodies yet somehow sounds otherworldly, an alien echo from beyond time and space.

Its double-album, SÖM SÂPTÂLAHN, was released in March, a result of a 2024 sold-out collaboration with the Fiske Planetarium. The record is named after a set of custom-crafted gongs cast from 600 pounds of reclaimed brass at the School of Mines that were tuned to a seven-tone scale before itchy-O used them to create a truly unique avant-garde offering.

But live concerts, particularly at Hallowmass, are where itchy-O truly thrives.

“It is not immersive theater. It is a ceremonial invocation rendered in sonic chaos, costumed ecstasy and collective transformation,” the transmission concludes. “Each year, thousands gather to experience a new phase of itchy-O’s mythic cycle, an interdimensional performance ritual driven by a massive rhythm section, industrial sound, and esoteric choreography.”

itchy-O Hallowmass 2025, with SOUNDCULT, 8 p.m. Friday, October 31, and Saturday, November 1, Summit, 1902 Blake St. Tickets are $53-$82.