I could see Miraidon and koraidon planning a trick on penny

Bede acting stupidly cheerful

bede kicking his feet and giggling

The Drifloon decides to not kill children for once

The protagonist's starters are sunkern, lumineon, and smoochum

ghetsis would also tell N that he isn't adopted

(but is that even a prank?)

I know this isn't an actual pokemon character but...

Mandjtv and Drowzee break up

N: Wouldn't it be silly if i didn't release this pokemon.

Ash being smart and brock not chasing random girls

Ash actually dieing or growing up