Cam is dipping a grilled cheese sandwich into a bowl of tomato soup when he feels the summons. He goes ahead and grabs it. Doesn't even drop the sandwich.
"What is that stuff?" wonders Sable.
"...Okay, know how if you're in an enclosed space, the air gets less airy? When you inhale you take a thing called oxygen out of the air, and when you exhale you're exhaling carbon dioxide. Carbon dioxide freezes colder than water ice does, and also it turns directly into a harmless gas that's already in the air instead of making a puddle."
"High school chemistry? You may be from a world with less advanced science than mine. In fact I strongly suspect it."
"You'd make it very cold, of course. Don't touch the dry ice. It's safe to get near as long as you're in the open but it'll freeze your skin."
"I can tell how cold it is with my hard-to-explain magic powers," she says. "But I couldn't make it that cold. I guess you don't have that problem. Anyway, I'm going to climb into this hole and spray it with green stuff. Please come along and kill monsters for me."
Eventually the hole opens out into a large round chamber with several smaller holes branching out of the bottom, and she sprays all of this and does a quick circling flight around the cavern to check if she missed any spots.
"Clear! Time to find the next patch," she says.
"Does it grow back?" Cam wonders. "After you've got it all on an island?"
"Not unless you summon the Wall of Flesh. Don't summon the Wall of Flesh," she advises. "You have to go all the way down to the underworld and kill a specific monster holding a doll and then drop the doll in lava, and your guide dies and a huge monster appears and tries to kill you, and then you get extra Crimson. So you're unlikely to do it by accident. But seriously, don't summon the Wall of Flesh."
"I... can't think of any earthly reason I might want to summon something called the Wall of Flesh by that mechanism for that result."
"Good! Because you shouldn't. I nearly died when I accidentally did it on my island. And now the place is infested with all kinds of even worse monsters than it used to have, and I live on one of the ones next to it that hasn't been changed that way. On the other hand, islands that haven't had the Wall of Flesh come by don't have the right materials to make wings."
"I can make wings. I mean, they won't look like you're an art installation, but I can make wings, behold." Waggle.
"I think mine are better," she says. "Are yours conveniently detachable?"
"I could take 'em off, but I don't know that I'd describe it as convenient."
"Mine come off and go back on neat as you please. I have a few other sets to swap them out with, but these are my favourite."
"Very nice. I've gotten used to having mine all the time. And the tail. They help me balance."
"I don't think I'm able to make a tail. But I've never particularly felt the lack."