When Mrs Percy first glimpsed the pig, it was standing in the middle of the road, looking "terribly bewildered".
It ran straight at the Percy's car, slamming into the bonnet on the passenger side.
"It was a bit scary, as we knew we were going to hit it," she said.
"We didn't want to screech on the brakes, as the car behind would have gone crunch into the back of us.
"It all happened so fast," she said.
No one in the car was hurt, but Mrs Percy said the impact made a deafening booming noise.
To her surprise, the car sustained only very minor damage, with the front panels slightly "knocked out of line".
The car's air-conditioning also failed to start for the remainder of the trip.
"It made one hell of a big bang, so I expected to see a couple of big dents in the front, or the headlights broken.
"He was a reasonably sized pig - very stocky, definitely not a tiny thing.
"We were quite surprised it wasn't worse."
The Percys were further surprised to see the animal running up a driveway.
After stopping in Featherston, the family drove back to the site to ask if the twonearby households were missing a pet pig.
But none had pigs of that size, and the offending swine was nowhere to be found.
"There was no blood up the driveways, or anything - he just disappeared," Mrs Percy
"I think by now someone's found him, and had a nice tea."
Mrs Percy said she will contact her insurance company, and take the car to the panelbeaters.
Though she "feels sorry for the poor pig", she can see the humour in the situation.
"I thought with all the stories about fires, houses being broken into, and drownings, this would give some people a chuckle."
