The annual event - set for Saturday - celebrates Earth Day with music, dance, costumes and marching. During its 13 years, it has included flies, butterflies, penguins, jellyfish, whales, crows, a lot of fish and a giant tree.
This year, among the characters will be a life-size rhinocerous s urrounded by a pack of hyenas.
"It's 12, 13 feet long, 6 feet tall - basically a sort of accurate rhinocerous," said Parker Mac Cready of Olympia who designed the creature. "It has some moving parts.
"It actually rolls on wheels, and the head turns back and forth with the front wheel, which is part of an old bike, and then there are levers off the back wheels that make the legs move in a sort of realistic way. There are a lot of moving parts."
Last year, 1,500 people registered for Procession - many at the last moment. That's down from 3,000 prior to Sept. 11, 2001, said Nicole Mercier, the president of the board of Earthbound Productions, which puts on the event.
Some participants have been doing papier-mache, sewing and practicing dancing and drumming for a month or more to perform in the event. Others will wake up Saturday morning and pull something out of the closet.
"People who have anything they were thinking of wearing should come on down," Mercier said.
When they first participated in Procession, MacCready and his family were the last-minute types, he said. He moved to Olympia in 1993.
"We've been going most years since we've lived here," he said. "The things that we've made have gotten a lot more elaborate. When our older daughter was really little, we'd be in the group with the cardboard butterfly wings, but it's gotten more involved over the years, so it's a major one month building project instead of a one day project."
MacCready and helpers have worked in his home workshop because the rhinocerous required welding. In addition to bicycle parts, the rhino includes a buggy used to tow children. A child can sit inside and steer.
"I guess when you sit inside this, you feel a little bit like maybe you're a rhinocerous," he said. "It's this big body, and it moves around in a lumbering way."
Many of the preparations are going on at the Procession Studio at 115 State Ave. in the alley behind the old Capitol City Press building. It's open from noon to 10 p.m. - and sometimes much later, especially as the procession draws near.
"It will be pretty chaotic coming in the Friday night before," Mercier said. "There are a lot of people who do that - come in and make a whole creation in 24 hours, as crazy as that is."
The costs of renting the studio and a larger dance rehearsal space at 525 Cherry have really added up, she said.
"The expenses we've had this year have been more than we've ever had in the past," she said. "We're up to $8,000, and being that there's no public funding, we are depending on donations."
Mercier said she's proud that the procession has maintained a public art studio for so many years.
"There's so much talk about doing an art studio in this community," she said. "There've been roundtables and discussions at the Olympia Center. We're the only organization that for 13 years has had a community art studio consistently."
Obviously, the procession can take a lot of work, but many participants only want more.
"If I can pull myself together, the girls and I are going to make some costumes this week," Sydney Hann of Olympia said Tuesday.
"I'm just sorry Procession can't happen two times a year."
