This looks really potent, but if you want your cheap removal you have to wait until the end of turn the permanent you want dead enters the battlefield to strike. Still, a very fitting way to flip someone off.
It is, but in the other hand paying 5 mana, killing a thing and pumping a creature to get a favorable attack/block is a HUGE blowout. Like, "pretty much win the game on the spot at Limited" huge. Either way, it's premium removal and a fantastic design + flavor but probably not quite there for Constructed.