You tried multiple times to escape from CHANSEY. But it's unworkable, since it's a battle. You don't have any Pokémon to fight it back. An trainer, with no skills, no freedom, but just an hopeless and despair individual.

Enemy UHCAKIP used !

The 50 leveled CHANSEY took too much damage! It fainted. Now you have CHANSEY, it heals your health if yours was low before it dies. That malicious Pikachu named UHCAKIP looks different than the original one. Now UHCAKIP is its turn to fight you...