In the TCG, Charizard is often rare and strong
So, almost every card incentivizes you to switch back and forth between the two sides whether to adapt to the situation, or to repeatedly farm value from each side a la Huntmaster of the Fells
What affects the value of Porygon
The first time you amass, you create a 0/0 Zombie Army token and put a number of +1/+1 counters on it equal to the number of amass
This is an entirely different error than a piece of tape stuck to the surface of the sheet which has been printed on top of, but looks almost identical without close scrutiny
Creatures (20) Lands (23) Spells (17) Sideboard As a two-drop that rewards you for playing cheap cards, it has frequently been used as part of a beatdown plan, giving you more fuel to keep snowballing advantage