reading the optional changes in Porygon-Z's dex entry:
"Conversion can be used with Dark Pulse and Nasty Plot (and a fourth move like Substitute, Recover, or another attack). Adaptability will make Dark Pulse as powerful as Tri Attack would once Porygon-Z is a Dark-type. The strategy takes two turns to set up, though: one to Conversion, making Porygon-Z a Dark-type (with STAB Adaptability Dark Pulse), and another to Nasty Plot, so you can do some damage. Using just Normal- and Dark-type moves will guarantee Conversion's turning you into a Dark-type. However, you can take a gamble and use a second attacking move as well."
this kind of made me lol in confusion? why would porygon-z ever want to do this?