I don't think I ever explained Passives so uh quick explanation, very very summarized:
Passives are basically a second ability that every Pokemon has active at all times and arn't affected by neutralizing gas or mummy stuff. They can be as harmless as say Run Away (Rapidash) and Frisk (Hisuian Typhlosion) and as Powerfull as Iridescent Fur: Color Change/Protine/Ice Scales/Fur Coat/Fluffy/Thick Fat all in one (Extreme Hyper Mega Eevee) Or Origin Plates: The User's moves will always hit,crit,and split the opponese defense stats in half and its always supper effective. However the user also has this effect applied to themselves. (Extreme Hyper Mega Arcues)
Uh... Don't worry about extreme hyper mega's as Theirs only 3* so yeah :3