He says that certain artworks - and the ideas behind them - have the power to provoke this sort of response from the public is positive because it shows people care.
Since then, Mitchell has exhibited in about 29 solo and 50 group shows around the world including Brazil, the Netherlands, Switzerland, Hong Kong, Australia and the United States and at art fairs from Singapore to Slovenia.
Now a lecturer in sculpture at AUT's School of Art and Design, Mitchell continues to make art which investigates the connection between tangible objects and intangible phenomenon and our senses and consciousness.
His Venice artwork will maintain this interest and is described as an ambitious new piece that will consider how different forms of knowledge intersect across "the visible and the invisible."
"The sculptural project will be simultaneously present whilst hiding in plain sight. Broadcasts that give voice to invisible realms and phenomenon will be transmitted throughout the city of Venice, conveyed by modern and contemporary technologies."
Creative New Zealand will give $700,000 across two years toward the project. It will be curated by former Auckland Art Gallery principal curator and head of programmes Dr Zara Stanhope, now at Australia's Queensland Art Gallery, and US writer/curator Chris Sharp, who's based in Mexico.
The selection panel includes art gallery and museum curators, academics, fellow artists and NZ at Venice Commissioner for 2019, Dame Jenny Gibbs.
Gibbs says the panel was unanimous in its decision and agrees the artwork may be challenging.
"But we always think if we take a bit of a risk, we end up with a more exciting project and I think we all like being challenged a bit," she says. "It is hard to visualise but I think people will find it intriguing and with an air of mystery about it."
Gibbs says we've never sent a work like Mitchell's to the La Biennale di Venezia, the world's largest contemporary art fair, and it will continue to show the depth and breadth of art being created in NZ.
Artists who have previously represented NZ are Peter Robinson and Jacqueline Fraser (2001), Michael Stevenson (2003), et al. (2005), Judy Millar and Francis Upritchard (2009), Michael Parekowhai (2011), Bill Culbert (2013), Simon Denny (2015) and Lisa Reihana (2017).
Mitchell says he's naturally thrilled that his proposal was the winning one.
"In working toward a project like this, you have to be able to project yourself into the head space of having actually been chosen but you never think it will happen because it's so competitive," he says. "I'm just very honoured to be part of this legacy."
He flies to Venice this week to start looking at locations for the physical component of his work then heads to Japan where he is exhibiting work at Tokyo's Mori Art Museum. The museum's website describes Mitchell as "an artist who conducts research on the energies and dynamics of the invisible world from artistic, scientific and historical perspectives."
He says the exhibition plays on the word "iris" - a part of the eye, a flower, part of a camera and the Greek goddess personifying rainbows. As with several of Mitchell's recent exhibitions, fragrance plays a part.
"I'm thinking about the eyes - the ocular - and the nose and our sense of smell - the olfactory - and the connections between these senses and experiencing the world through multisensory inputs," he says.
"When you smell something, you're having an engagement with an object but at a molecular level."
Earlier this year, Mitchell made Buried Gemstone for Waiheke Headland Sculpture on the Gulf. As the name suggests, it was a large gemstone buried along the route at a site known only to Mitchell. He hoped to encourage viewers to think about the role imagination in the arts and how ideas might be buried in objects.
"I had a lot of fun with this because I went to talk to kids at a couple of primary schools and they loved the idea," he says.
"They got very enthusiastic about the idea of there being 'buried treasure' and the possibilities around it. I was asked questions about if you had a dog and you were walking the dog, would the dog be able to find and dig up the treasure.
"I think as we get older, we get more cynical about the world and we think someone might be trying to pull the wool over our eyes but we forget about the importance of imagination, of things we cannot see."
The Biennale Arte opens every two years in May or June, involves more than 80 countries and runs for about six months. The 2017 event closes at the end of this month and has seen NZ artist Lisa Reihana win widespread praise of her video installation, Emissaries.
