Pikachu lost 20 XP!
If you ever do get stuck in a Pokémon playthrough - there is always the option to just do some grinding battling some wild Pokémon to strengthen your team.
Well - what if every battle your Pokémon fight causes them to lose XP? How about using a Rare Candy instead? Nope - that causes your Pokémon to level down too.
here's an example...
An insane run which challenges everything a normal Pokémon playthrough represents - another hilarious video from SmallAnt.