When you're camping outside, you discover bugs you never knew existed.

For Sokka and I it was a whole new world of discomfort. We'd never had to deal with hornet crabs or locust rats or swarm midges in the South Pole and we weren't going to take it lying down now! Toph had it even worse - all she could do was listen out and wait for the pests to land on her before taking a swipe. She'd wake up every morning with fresh bites and channel this frustration into a grinding lesson with Aang.

Only Aang was different. He seemed immune to any sense of spite. However many critters were zigzagging around our campfire, braving the smoke to get at our dinner, he'dt brush them away as gently as if he were waving at them. Whenever Sokka raised the beetlefly swatter he'd bought at the market, Aang would frown disapprovingly. I had to look away when he made this face, not so much angry as bemused, and so monkish. You could almost believe he was really one hundred years older than us.

One time, Aang was bitten by what he said was a hermit Butterfly. Those are bugs that latch on to their host with their teeth and burrow their head in a little way, to suck the blood. Nasty enough! He showed us in reckless surprise one day at the camp site after a dip in the lake, its tiny black body lodged upended iin his arm, its brilliant purple wings half-folded under its shell. But Toph, after Aang guided her hand to the bug, let out a gasp and said it wasn't a hermit butterfly at all, but a much more dangerous critter, an Angler Mantis. "They lay eggs inside you! We have to get it out!"

"No," Aang insisted, "I'm pretty sure it's a hermit butterfly."

"What does it matter?" Sokka said. "Whatever it is, let's dig it out. This is self-defence. You can't become a bug hotel, Aang."

But Aang insisted on waiting to see if the 'hermit butterfly' would drop off after feeding, even though there was a chance that tiny eggs were about to make a home in his forearm. Eventually we convinced him to try and remove the embedded bug without killing it. We tried every gentle variation of pest removal we could think of, from fire and ice to salt, but with no luck. The "hermit butterfly" clung on.

Finally we went into a nearby town to find some help. I had to quell the suspicion that Aang's lips were turning just a tiny bit green.

We found the smoky tent of a passing apothecary outside town. It was getting dark, but Aang still seemed unconcerned. He was convinced it was the relatively-harmless hermit butterfly. He even he looked cheerful. "I wonder what she'll try!" he mused, as the old woman huffed around her plucky patient. She tried heating needles to pluck the bug's wings; she tried hot and cold treatments; she tried drawing it out with pungent fumes. Aang reacted with mock fear whenever she revealed a new prop, but he seemed more excited than concerned, like a kid waiting for a magician to perform his next magic trick. The more excited he got, the more frustrated the old apothecary became. "I never saw someone so cheerful about having an angler mantis lodged in their arm," she huffed. "If it won't come out alive, the only way to expel it without it releasing eggs is to slice it clean through."

Now this was serious. We all insisted it needed to go. But Aang held back. "They're endangered," he insisted. "At least, they were a hundred years ago."

"This is no time to be worrying about the environment," I said stiffly.

"Wait Katara. I have one more thing to try."

Taking off his waistband, he wrapped it around his arm and pulled it as tightly as he could, forming a tourniquet just above the black-purple brush of the bug's back. His arm slowly reddened.

I was losing confidence now. I pleaded with Aang again and again to let the apothecary slice the angler mantis in half with one chop. I'd even settle for letting Sokka have a try. But Aang sat calmly in the light of the fire, his arm darkening to a wine-ish colour. After a few minutes, he started to gently rub the mantis' back between thumb and forefinger. Sokka and I watched in disbelief. His arm was numb, flopped over his knee. He kept rubbing, chewing his lip in absent concentration. Then with a sudden - click! - of the mandibles, and a little yelp from Aang, it popped out of his arm and into his palm, legs wriggling. I shuddered. Watching it wriggle, I resisted the urge to give Aang's grinning face a slap.

The apothecary's eyes glittered. I suddenly wondered if she knew who this was.

Taking the bug carefully in both hands, Aang ducked out of the tent with us close behind, and released it into the night. The purple wings opened and the angler mantis zigzagged towards the moon.