The name Swamp Thing is a play on the cartoon character of yesteryear and Barkers' childhood fascination with swamps in his hometown of Rotorua.
"There's also a type of blues called Swamp from the Louisiana area. We went there in April and May and had an artist in residency in Baton Rouge - it was a bit of a swamp pilgrimage."
All music festivals are held over those two months because crawfish are in season - offer the delicacy at your event and the crowds will come - or so the Kiwi duo discovered.
"Everyone eats it, if you offer it the gig will be packed - that's what we did."
Time in the recording studio has been another big part of 2015, with a third album two thirds of the way through and fresh inspiration from their trip bringing something a little different.
"We are essentially blues based, but it ventures into other influences".
They have also been playing a lot, hitting the road wherever possible - a life Barker was no stranger to having been an integral member of The John Butler Trio for 7 years, before heading home across the ditch to be closer to family.
Napier is a regular stop off for Swamp Thing, who have worked to secure a legion of loyal fans or "swamp moshers".
"We have been lucky in Napier, we have a really fantastic following. We have been to Sanctuary Sounds [music festival] and through that we have met part of the community that hangs on the fringes."
Part of their show is the "spectacle" of Haua, whose stage presence has veered toward Elvis after a 4th of July performance dressed as the King.
INFO
WHAT: Swamp Thing
WHERE: The Cabana, Napier
WHEN: 9pm, Saturday
COST: $20, general admission from eventfinda.co.nz