"Huh," that was new, people usually called his name nerdy or old-fashioned, "Thanks, li'l buddy."
Bart watched Null exit the weird room, unable to not look a tad bit bewildered by the skeleton's overall reaction to just… Entering--did this count as entering, though--Waterfall. Boring ol' Waterfall. Hadn't he been through it already? It didn't look like there were any other exits or entrances--?
As the cat-man turned back to take a look to confirm or hopefully disprove that thought for the sake of his own sanity, he opted, instead, to move back further when said room's other occupant finally left its confines.
Right yeah nope he didn't like how that guy was looking at him. Bart about-faced and instead opted to try and make his exit as the creepy tall guy followed what the cat-man can only assume was his friend.
He didn't get far. Gaster, opting not to answer any of Null's questions, grabbed the cat's tail, which got a startled yelp, with a hand materializing for that very purpose. Tail thus in hand, he dragged Bart on back over to stand, involuntarily, beside him, near where Null was crouched.
Gaster, who glanced at the cat and pointedly nodded towards Null. He didn't want to speak in the presence of yet another Monster, and while the cat had been ever so ready to sneak away... If he could pawn Null off on a guide, then he could work on a kill switch for this world that he could activate when it was time for them to leave. A simple plan; whether or not it was an easy one was yet to be seen.
"… Oh," said Bart, ineloquently. This was his afternoon now, great, cool, fantastic. Could be great acting practice, though. Tour guide for… Aliens? They had to be aliens. Who got that awestruck by shiny rocks and mushrooms? It would explain the weird TV noise stuff around the smaller one, too, and the weird room. Probably. The cat-man cleared his throat, threw on a much more confident and suave--if one were to ask him, anyway; an opinion tainted by extreme bias--demeanor, and looked down at the fungi Null was admiring. "Those, my esteemed extraterrestrial friend, are what we Underground Earthlings call gloshrooms. Whoever named them wasn't very creative, am I right?... Aaanyway. They're kind'a all right when they've been stuffed with snails and baked for a while. You can get 'em like that at The Queen's Landing. Which, coincidentally, is where I was heading."