Sorry for the wait! The original processor seems to have missed this.

The effects of the corrupted evolutions have rendered Porygon-Z extremely... giggly. Or at least, the strange staticky, glitchy sounds it emits are vaguely analogous to laughter. It laughs at just about everything, but primarily at other people's misfortunes. Those who would berate it for its lack of empathy are unnerved by its swirling eyes and its tendency to slowly revolve its head 180 degrees until it's upside down.

Honestly, it's just creepy.