When an object becomes a copy of another, what happens to its original characteristics?

When an object in Magic: The Gathering becomes a copy of another object, it loses all of its original characteristics and adopts those of the object it is copying. This means that attributes such as power, toughness, card type, abilities, and any specific characteristics from the original object are completely replaced by the characteristics of the copied object.

In the context of the game, this is critical because it allows the copied object to function without reference to its original state. For instance, if a creature becomes a copy of a different creature, it would have the same power and toughness, abilities, and any relevant characteristics of that creature, discarding its original attributes entirely.

The other options suggest retaining some characteristics or creating a mixture, which does not align with the rules governing object copying in Magic: The Gathering. Therefore, when an object becomes a copy of another, it is indeed the case that its original characteristics are lost and replaced by the characteristics of what it is copying.