Casford, 23 at the time, was on a date with his girlfriend when he said "something like out of a movie" unfolded.
"This little monkey come up and stuck it's little paw up on the window against her hand, like something out of a movie, and she said 'oh my God, I want one of those' and I thought, 'F***, that's what I'm gonna get her, I'm gonna get her that monkey'," he said.
"Next thing I climbed in there and went and got it, two in the morning.
"I was too scared to stick my arm in there and reach around, so I lit the lighter, I seen his little eyes looking and grabbed it and shoved it in my bag and left.
"I make it to the fence and it's all electrified at the top."
Casford said he thought he would climb the fence but things went "real bad".
He said he panicked when he approached the live portion of the fence, dropped the monkey, and tried to jump.
He fell more than 8 metres on to concrete and "blew all his teeth out" – literally.
He described the fall as the "meanest ground shock ever" and was starting to think at that point, "this isn't a good idea".
But Casford didn't stop there – broken leg and all. After he got his leg put in a cast and his teeth fixed, he caught up with his missus for a date to go shopping because it was her birthday the next day.
He saw the police go past and started running but with only one leg, they soon caught up with him.
The day Casford was sentenced for the incident he was also sentenced for an unrelated spate of violent offending.
He had pleaded guilty to a number of incidents, including an unprovoked assault on a man waiting in his car at traffic lights, an alcohol-fuelled attack at a dairy in Westport, and assaults on a Wellington City Council community safety officer and a night shelter resident who refused to hand over cigarettes.
The judge sentenced him to two years and seven months in prison for all of the offending.
Once in jail, Casford told New Zealand Today he felt "rats**t".
"But a bit of relief, like, right, we can deal with all of this," he said.
After going to jail on his girlfriend's birthday, they didn't stay together, but he told the program "you never know what the future holds".
Convinced Casford's twisted romantic comedy plot needed a happy ending, Guy Williams helped the Lothario attempt to win his ex over.
He re-enacted the scene in 10 Things I Hate About You, singing Can't Take My Eyes Off You to a band in a cricket stadium for his ex sitting in the bleachers.
"It's almost like a beautiful rom-com … almost," Williams said.
In all seriousness, the monkeys were injured and left traumatised after the ordeal.
After pleading guilty, Casford attended a Restorative Justice meeting with zookeepers, who said it was a blessing he was unable to catch any of the monkeys, for his sake and theirs.
"You said you were, and I quote 'high as a kite'," the judge at sentencing said.
One monkey had a haematoma on its elbow and others had scratch marks.
"I don't know what happened in the squirrel monkey enclosure. The squirrel monkeys know. You say you couldn't find them and I don't speak squirrel. What I know is that by daybreak all the monkeys were distressed, two of them were injured, and you had a broken leg, two fractured teeth, a sprained ankle, and bruises on your back," the judge said.