"Exactly!"

"So have you been doing any other interesting science recently?" 

"Depends, are magic tricks interesting science?"

"Sure! What sort of magic trick?" 

"Check this out, check this out!" He runs over to the pool; by it, there's a smaller pool in the sand, of lava. He gets in a boat, pauses for several seconds, does some weird things with his hands, gets out of the boat, and then jumps onto the lava. If Quackity looks closely, he'll notice that Fundy's not in fact standing in the lava, but hovering slightly above it.

Oh god he's about to do the thing Dream did isn't he why does everyone do this-- 

--except Fundy isn't... sinking...? And doesn't look to be in pain at all? 

He does his level best to relax but there's no recovering how much he definitely did not look remotely chill just now. "Huh. Neat." 

A vital part of the joke is tricking people into thinking you're going to jump into lava. Fundy does not judge Quackity for being alarmed by this. He laughs and twirls around, jumps once. "Cool, right?"

"...yeah! Cool!" This is not even untrue. "How are you doing that?" 

"Hold on, watch this." He goes back onto the sand, gets back in the boat, and then starts making a pile of sand behind Quackity; it's farther than he's able to reach but Quackity can see the sand disappearing from Fundy's hands and appearing behind him, pawprints pressed into the top.

"...that's so cool!! What!!" 

He's still doing something with the sand in his hand but there's no longer any sand being put down that Quackity can see; a few moments later he gets out of the boat again, walks a bit away, and walks on an invisible staircase up before bowing. "A good magician never reveals his secrets."

Light, laughing applause, which could be either sincere or yes-and-ing the bit, as Fundy prefers to interpret it. "Then I will not ask for them!" 

Back in the boat; a ghost hand taps Quackity's shoulder from behind as Fundy's hand reaches out to tap the air. "Now break the sand under me?"

He is sort of expecting this to mysteriously fail somehow but he'll try? 

The sand breaks! The boat is now floating exactly where it was, no longer held up by anything, with Fundy in it.

This is marginally less impactful because Q knows he doesn't have any idea how gravity works, but he looks appropriately impressed with it anyway! 

And when Fundy gets out of the boat it falls down on the ground again.

"Ta-da! Magic tricks!"

"Magic tricks!"

(The amount that he visibly thinks this is incredibly cool is-- not insincere? It's on purpose, though.) 

"Woo! Yeah!" He pumps his fist in the air. "I do not actually remember what else we were doing!"

"I was going around trying to put faces to names, and you were asking me about economics. I think." 

"You know my name now! And my face! I know... slightly more about economics!"

"I do! And you do! It was really cool meeting you, thank you." 

"I'll let you know if I can get the powdered snow to do anything cool, alright? And if you ever want to--talk, or hang out, or, or, anything, I'm usually...around here...doing nothing..."

"I'll hit you up," he says, and means it. Smiles at him one last time before walking away. 

Is Foolish doing something that looks easy to interrupt, Q doesn't know his world's Foolish super well but is familiar with his tendency of taking on Projects. 

Foolish is placing white concrete powder in water and then mining the white concrete. He's definitely got a rhythm to it but doesn't look to be doing anything that would be too annoying to stop and then pick back up later.