As Bailey asked him about his other Pokemon, Charlie paused for a brief moment; and taking in that, like Jess, she seemed friendly, he thought quickly and replied with-

“Oh, my other Pokemon? Uhhhh… It’s nothing particularly special, just a Scatterbug that jumped me a few minutes before I bumped into you guys, really. Don’t even know if I’m going to keep i-”

And then the relative quiet of the forest and the conversation was completely perforated by a sharp, shrill sound of fright. 

As with Bailey, Charlie’s initial reaction to the shriek coming from the edge of the forest was to freeze and flinch; zoning out for a brief moment as his thoughts began to roll about his head in minor panic.
What the hell had happened to produce a noise like that?!?

Whatever it was, Charlie wouldn’t get the chance to dwell on any thoughts about it; he noticed Jess mumble something and move towards the source of the noise excitedly, and a moment later he was brought back to attention by Bailey addressing him again.

"I guess we should hurry then," She said to him, pointing out a few locations on the map before taking off after towards the sound of the shriek and her Duskull. 

“... I guesso,” He said, quiet enough that only he would hear it, before following after the girls with Phil in pursuit.

Phil didn’t seem shocked or disturbed by the sudden sound; if anything, the little Ghost seemed as excited as Jess did at the shriek. Obviously, something FUN had just happened a short distance away, and he wanted in!

Anyway, within a minute, Charlie reached the source of the commotion, just a little shy of Bailey’s arrival; catching sight of a highly amused Jess, an equally amused Duskull and a very pissed-off Miu.
Who promptly yelled out in frustration and took into the forest again after what he could now make out to be a Pidgey attracted by a very unconscious Caterpie. 

“... What the hell happened?” He asked aloud, his sheer curiosity and disbelief overtaking his nerves as he failed to piece together what could have happened to warrant a shriek that loud.

Phil, on the other hand, seemed to lose interest in whatever had happened as soon as he realized it was over; and with a sigh of disappointment, faded back into floating about, sneaking a couple of glances towards the other Ghost-type present as he did.