The Legendary Diving Pokemon was the subject of Pokemon The Movie 2000, a film that captured the interest of kids during what was likely the peak of the Pokemon zeitgeist
The -3 lets you destroy a target creature, and finally, the -6 gives you an emblem that states "whenever you gain life, target opponent loses that much life." Given that this card only costs four mana to cas t, it, like most of Witherbloom, is quite finely balanced and should see plenty of play across Standard and Commander
If you are the one being attacked, you can use your Pokmons defense mechanisms if they have one, and also keep track of how much HP you have left
Kudo, King Among Bears evens the playing fieldthough you can break the symmetry by loading your deck with anthems like Flowering of the White Tree and Maja, Bretagard Protector that ensure you have the biggest creatures