"People don't realise there are families living in poverty right on their doorstep and we're trying to bring smiles to people's lives," says Quake Kid.
Today Flat Man is planning his 50th flat delivery. Quake Kid, who has been his friend for years, was stunned to learn of his mate's double life.
"I'd heard of this guy Flat Man around campus, but when he came to me and said, 'Mate, I can't handle all this, can you help me', I was really shocked.
"It blew me away. His heart is two times too big for his body. But I responded with big enthusiasm and wanted to help any way I could.
"I've always been a little bit too into superheroes ... I think that's maybe why Flat Man asked me. I've got way too many Spiderman things in my bedroom."
The pair are sharing the financial burden of the stunts, which have cost them hundreds of dollars.
But they are starting to receive donations from fans across the country, enabling them to do even more doorstep deliveries for worthy causes.
A Christchurch car sales company has loaned them a Flatmobile - an immaculate yellow 1970 Chevrolet Camaro.
"We're getting nominations (for deliveries) from friends of families who still can't use their own toilet, not able to drink their tap water," Quake Kid said.
"Flat Man and I are just shocked by it. We put together a couple of really big hampers together for some families who were hit hard in the quakes.
"One family were in and out of hospital with a kid with cancer and needed lift, so we put something awesome together for them and dropped it off in the middle of the night."
A Facebook page dedicated to the Flat Man phenomenon already has more than 2500 friends.
But as their legend grows, the dynamic duo are working harder than ever to protect their true identities.
"The anonymity of the whole thing is key. If people knew who we were, it could ruin everything," said Quake Kid.
"My own mum doesn't know. Only Flat Man's mum knows who we are. We use her house as our base of operations, where we get ready for missions and she cooks us dinner.
"She's kind of like our Alfred (Batman's butler), I guess."
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