Honestly, my plans are pretty vague at the moment, but... they're tending to show up around reincarnates, even while they're keeping their distance, right? So Fred and Hajime run into each other, as they just did, and something draws their attention to the Vermini. Then maybe Hajime explains something about them being bad news or enemy agents or related to the minebats or whatever, or maybe Fred just gets unnerved and lets fly a Spire or something. Does that suit?

And yes, just a cat. I was considering an injokey thing about it pushing potato chips at him, but that'd really be too much setup for not enough payoff.