"The river is emitting sounds of distress," notes Streak. "The river or some creature in it."
"...Rivers per se rarely emit sounds of distress, although we did just meet very menacing trees, so who knows. If there's creatures in the river maybe Cordy can talk them into giving us a ride."
They're close enough now for Streak to make out details. "It. A singular creature. Very large and snakelike. And I see what you meant about seeing the other side, Joy. The creature's thrashing is causing large waves and considerable spray."
"That'd make fording tricky even if it were shallow and otherwise calm and we were all experienced aqua-ponies."
A little farther along, and they're close enough for everyone to make out details - and hear the river creature's despondent wailing.
"BAWWWWWWW," sobs the serpent, thrashing miserably.
"Excuse me? Sir?" says Clarity. "Why are you crying?"
The serpent regains enough control of himself to reply. "Well, I don't know," he sniffles, "I was just sitting here, minding my own business, when this tacky little cloud of purple smoke just whisked past me and snapped my left fang clean in half, and now I'm positively unpresentable!" He opens his mouth to draw breath for more wailing, displaying a broken fang that does not match the one on the right.
"Aww," repeats Blaze. "What a mean cloud!" She comes up closer to the river and peers at the serpent's mouth. "...hmm, I wonder," she murmurs to herself. And a little louder: "Hey, mister serpent? How would you feel about a replacement fang? In, say, red?"
Clarity looks confusedly at Blaze.
She sits down on her hindquarters and takes off her front boots, then extracts several small tools from where they were previously hidden in the base of her mane. Soon she has detached the front plate from the right boot. With its sharp point and wide curved base, it's a nearly perfect match for the missing part of the broken fang, plus some overlap to get it firmly seated.
"There," she says, holding it up. "I'm just not sure how to get it attached. Any unicorns want to lend a hoof? Or a horn, more specifically?"
"Technically it still works, I just can't wear it anymore; it won't stay on without the front plate. But hey, I've got three more."
Clarity floats up the boot-part to the serpent's open mouth, and sticks it on. The serpent grins toothily at his reflection in the water, then beams. "Fabulous!" he proclaims. "Thank you ever so!"
The river is calming down as he stops heaving his coils around in dissipating distress.
"...Um, Clarity, I don't suppose you have room in your saddlebags...?"
"Oh, do you need to cross?" inquires the serpent. "Allow me." And he forms a tidy bridge.
"It's no trouble at all," says the serpent magnanimously.
Across go ponies!
"I thiiink that's the castle up ahead," says Joy.
"It looks like it! We made it - except for the obvious chasm all around the place, anyway. Is there a bridge? Or, it looks like there's room to fly, if the fliers want to make a few trips..."
"There was a bridge," she says, pointing a hoof at the bridgeposts. "It may be possible to repair it."