If they do, then as blockers are declared in the combat phase, that battle's protector chooses which, if any, creatures they control will block that attacking creature
It is often unexpected and it takes explaining too
When your opponent's monster declares a direct attack, if you have another "Ninja" monster in your Graveyard: You can banish this card from your Graveyard to target the attacking monster, negate that attack
This is where deck synergy comes into play
VioletTotal Card Sets516SARSpecial Art Rare3URUltra Art Rare8SRSu
Although you can't play with numbers as big as you can in stocks and real estate, the barrier to entry is tiny (even a 8-year-old kid can come up with the money to buy some under-valued Pokemon cards) and the potential for profit is huge