I always saw it as sort of a kindly punishment. Coriakin didn't want to hurt them, he just wanted to show them how ridiculous they really were by making look as silly as they acted. 

The change does seem to hit home somewhat considering how horrified the Duffers were at their "ugliness," and how desperate they were to do something to hide it. It also forced them to look to someone else- namely Lucy- to solve their problems, whereas they had hitherto distrusted and ignored Coriakin in favor of their own buffoonish counsel.

We get the sense that he's amused by them being monopods, (laughing along with Lucy when she first sees them) but he also makes it clear that he had refrained from using direct force to solve the Duffer problem, such as making them not believe anything the Chief says. He even says he looks forward to the day when he won't have to use magic in his governance of the Duffers at all. It's as if he put the spell on them to prove a point and teach them a lesson rather than to hurt them seriously or have a laugh at their expense.

It was a punishment, but it was also to entertain Coriakin. The story does not say whether the author agrees with his doing that to them, and I think we must view Coriakin as imperfect, not a sinless character like Aslan.

I can't give a better answer than Cleander and Coracle, but just as an interesting side note, Lewis almost certainly got the idea for the Monopods from a medieval map of the world (c. 1300), the Hereford Mappa Mundi, which is on display at Hereford Cathedral. One of the many mythical creatures included on the map is a Sciapod (literally "shadow-foot"), i.e. a man-like character with only one leg and a foot so big it could be used as an umbrella...

(Picture from Mappa Mundi Hereford)

But as to exactly why Coriakin decided it would be a good punishment to turn the Duffers into these, I'm not sure!  

Interestingly, it's also mentioned that he had a bearded mirror in his mansion; its purpose is unknown, but the implication is that it could be used to prank his guests. Wonder if the author implied that Coriakin has a peculiar sense of humor?

You know, I've recently read that it could also be a kind of self-irony on Lewis' part. You know, the Dufflepuds eventually learned to make use of their condition that they thought a curse (i. e. using their large foot as a boat, etc.) And Lewis himself was born with only one functional joint in each of his thumbs, which made him unable to play sports games and do a lot of other stuff, so he resorted to writing - and became a great writer, which probably wouldn't have happened had he been born with normal thumbs. Given that Coriakin's relationship with Dufflepuds was clearly a metaphor for humans' relationship with God, it's quite likely IMO that Lewis intentionally drew this parallel.

@courtenay

The Mappa Mundi is something i've been pondering for a while, not just because its one of the only other places i've ever seen Monopods before (though i'm aware they do exist in wider mythology) but that it also depicts alot of other creatures which are prominent in VoDT such as Dragons and Mermaids, and perhaps most crucially that the map depicts a flat world in which the realm of man exists at the centre, and the realm of god exists beyond the edge of the flat world.

I'm often skeptical when people attempted to ascribe singular unifying theories to a set of books (such as the "Planet Narnia" theory) particularly which Lewis clearly draws from all manner of sources to create his world, however it also seems improbable that a man of Lewis' education and background would be unaware of this map, and so the similarities cant just be coincidence.

And yet i dont think i've seen a single piece of scholarly research to suggest any association between this map and VODT. Is the connection too obvious and therefore not really worthy of further academic discussion? or has just no-one noticed?

Posted by: @icarus

And yet i dont think i've seen a single piece of scholarly research to suggest any association between this map and VODT. Is the connection too obvious and therefore not really worthy of further academic discussion? or has just no-one noticed?

I've certainly seen it cited more than once as his "source" for the Monopods, but I have to admit I don't think I've ever seen actual proof that it was. What we'd need is direct evidence that he had either visited Hereford Cathedral at some time and seen the Mappa Mundi for himself, or had seen descriptions and pictures of it in books. It's highly likely that he knew about the map, since the medieval world was his field of expertise, but how detailed was his knowledge of it? I'd be very interested to find out more about that.

To the main question, why did Coriakin turn the Duffers into monopods - I think the answer is "both".  I always did think Coriakin had a kind of twisted sense of humor, because if all he wanted to do was punish them, he could have turned them into bugs or mice or plants or something.  If all he wanted to do was teach them a lesson, he wouldn't have made it permanent; parents don't ground their kids for life, just a week or a month or whatever.  He would have to be really, REALLY angry to not just make it a day-long or week-long thing.  And if he were that angry, he wouldn't have turned them into something so hilarious!  But then again, for all we know, they were Duffers for a week and invisible for a day, before the Dawn Treader arrived.  Regardless, I think it was a bit of both, a punishment and a joke.  I do think he ultimately just wanted them to learn from it, but of course that's not how it played out.  btw that was REALLY interesting about Lewis' thumbs!  Didn't know that one. 🙂

But as far as the source, I think it's extremely likely that Lewis borrowed from it.  When I was a kid, we were once telling ghost stories around a bonfire; my first story was actually decent (and actually scared my brother a bit), but the second borrowed from MN.  The kid found a key that opened a door into a long, narrow hallway which was basically the Wood between the Worlds.  Of course I wasn't going to borrow the whole story, but my brother (who was reading MN at the time) saw right through it. 😀  But the point is, if a 16-year-old kid can take something he knows and apply it in a new and creative way to something unrelated, how much more can a highly educated author like Lewis?  And I'd be surprised to meet anyone who ever heard of the Hereford Mappa Mundi (I've only heard of Hereford because I was doing research for a story I was writing and wanted the name of a really small town in England 😀 ); so except for even more die-hard medieval enthusiasts than me, no one would be able to do like my little brother and say "hey, you ripped that off of..." (lol).  So IMO that's not too big a stretch.

Posted by: @geekicheep

To the main question, why did Coriakin turn the Duffers into monopods - I think the answer is "both".  I always did think Coriakin had a kind of twisted sense of humor, because if all he wanted to do was punish them, he could have turned them into bugs or mice or plants or something.  If all he wanted to do was teach them a lesson, he wouldn't have made it permanent; parents don't ground their kids for life, just a week or a month or whatever.  He would have to be really, REALLY angry to not just make it a day-long or week-long thing.  And if he were that angry, he wouldn't have turned them into something so hilarious!  But then again, for all we know, they were Duffers for a week and invisible for a day, before the Dawn Treader arrived.  Regardless, I think it was a bit of both, a punishment and a joke.  I do think he ultimately just wanted them to learn from it, but of course that's not how it played out.  btw that was REALLY interesting about Lewis' thumbs!  Didn't know that one. 🙂

Thank youuu!!! ? I completely agree about his twisted sense of humor, and I believe there were some other indications of it. Most notably, the bearded mirror, and also, the fact that he didn't turn himself and the Duffers visible again and preferred to wait for Lucy to do that (the text implies that he and the Duffers have been invisible for at least several days, if not longer, because Coriakin mentions that he knew all along that Lucy would come, but wasn't sure of the exact day). Moreover, when Lucy came to his house and read his book, he was presumably watching her the whole time, but didn't try to communicate with her until she read the spell and made him visible (in the BBC version, he appeared in exactly the same room as Lucy, so it's clear he was watching her). In general, one gets the feel that Coriakin was enjoying the whole situation, and everything, from him turning the Duffers into Monopods, to the Duffers turning themselves and him invisible and thinking that he could be right behind them because they couldn't hear his footsteps, to Lucy coming to his house and reading his book, was a source of amusement for him.

One more thing I was curious about: I remember that in the Last Battle, the Dufflepuds were among the creatures entering Aslan's Country, implying that Coriakin did after all manage to enlighten them. I wonder if they went their own way after that, or if they chose to stay with Coriakin in Aslan's Country?

Posted by: @mickey

One more thing I was curious about: I remember that in the Last Battle, the Dufflepuds were among the creatures entering Aslan's Country, implying that Coriakin did after all manage to enlighten them. I wonder if they went their own way after that, or if they chose to stay with Coriakin in Aslan's Country?

I am going to have to look for that when I read The Last Battle to my kids because I don't remember that detail.  It's been a while since I read it all the way through.

I love Voyage of the Dawn Treader and the part with the Dufflepuds and Coriakin is one of my favourite parts of the story but I always felt uneasy about their transformation.  It always felt over the top and cruel.  They seemed pretty happy with their new boating abilities but hopping around on one foot truly would be quite inconvenient and they had been so horrified by the change.  It's not something I ever really thought too deeply about though and I get the main point Lewis was trying to get across.  I always had hoped they'd be given their normal legs back.

“And now that they’re visible, are you going to let them off being ugly? Will you make them as they were before?” “Well, that’s rather a delicate question,” said the Magician. “You see, it’s only they who think they were so nice to look at before. They say they’ve been uglified, but that isn’t what I called it. Many people might say the change was for the better.”

Lewis, C. S.. The Chronicles of Narnia Complete 7-Book Collection (p. 721). HarperCollins. Kindle Edition.

As a kid after reading this I always assumed that he did it to make them better looking.  It wasn't until years later that it registered to me that it was a punishment.  

Posted by: @cyberlucy

“And now that they’re visible, are you going to let them off being ugly? Will you make them as they were before?” “Well, that’s rather a delicate question,” said the Magician. “You see, it’s only they who think they were so nice to look at before. They say they’ve been uglified, but that isn’t what I called it. Many people might say the change was for the better.”

Lewis, C. S.. The Chronicles of Narnia Complete 7-Book Collection (p. 721). HarperCollins. Kindle Edition.

As a kid after reading this I always assumed that he did it to make them better looking.  It wasn't until years later that it registered to me that it was a punishment.  

In fact, according to Coriakin, it was both: it was a punishment because they thought they were ugly in their new form, but in his opinion, they actually became better.