It will not overwrite effects that modify power or toughness (whether from a static ability, counters, or a resolved spell or ability), nor will it overwrite effects that set power and toughness which come into existence after the ability resolves
Anywho, this is a fairly boring hard counter that does the job and does so as reasonably as such things can be done
In multiplayer formats like Commander, its especially deadly in decks led by commanders like Kilo, Apogee Mind or Atraxa, Praetors' Voice, both of which thrive on counter-based strategies
Without a justification then you will not be able to convince people to alter their perspective of a card when you do have discrepencies between your lists
Charizard V 79/73 - Champions Path Holofoil The Pokmon Company Discard 2 Energy from this Pokmon
Blastoise V [W] Water Gun 30 [W][W][W] Torrent Canon 200 This Pokmon can't use Torrent Canon during your next turn