We are sticking them in REAL life...
they keep there appearance but all of their special traits are either nerfed to realistic standards are eliminated....
Squirtle is a "tiny turtle" so naturally in order to exist, he would follow the basic properties of all other turtle species- A hard shell, a hard skull, and bad mobility...turtles can also shoot water from their mouth, but it's not highly pressurized and only good for a distraction....squirtle's construction resmebles that of an actual turtle...nothing more other than it's tail which it can use for balance and recovery...
Pichu is a rodent.....small, light, mobile, and it's body structure gives the indication that it has a realistic mechanic to produce electricity...