The Copy copy ability does exactly what it sounds like - it allows Kirby to copy an enemy's power if it has one. He wears a white, high-tech visor, and fires a scanning beam. It will only destroy enemies that don't have a power to copy. Copy's Copy Essence Deluxe in Milky Way Wishes is found on the level ???. While it seems useless, seeing as Kirby naturally can copy an enemy, it could prove useful if one obtains this power first in Milky Way Wishes, as it would allow a player to temporarily take the powers of an enemy without a Copy Essence Deluxe. It is also useful in taking powers from certain enemies that cannot be inhaled easily, like mini-bosses, as Kirby does not have to KO them beforehand to take their powers. Copy is also the only way that Kirby can take Scarfy's secret copy ability, Crash.
Copy is perhaps most useful for its helper, TAC. When used by a second player, TAC essentially becomes a second Kirby, allowing the second player to copy his own powers. In Kirby Super Star Ultra, what also happens is that the icon changes to that helper icon and a question mark.
Kirby copies an ability from any scanned enemy. This ability is most useful against bosses, mid-bosses, as well as acquiring Crash from Scarfy and Mad Apple. If used on TAC, an enemy without an ability, or a boss, they will either be defeated or take damage.