Power Mimicry

Summary
Power Mimicry is the ability to imitate or replicate the abilities or powers of others. The methods and limitations of this ability vary between media, but users will generally need to encounter the power or the power's user in order to imitate it. The effects may be temporary or permanent, and particularly powerful wielders of this ability can combine the powers they copied for even more devastating effects.

Users
Some users include:

Mega Man, Bass, Proto Man, X, Zero and many other characters (Mega Man)

Phantom (MapleStory)

The Protege (Marvel Comics)

Rogue (Marvel Comics)

Amazo (DC Comics)

Medaka Kurokami (Medaka Box)

Rufus Lore (Fairy Tail)

Leo Regulus (Saint Seiya)

Ryoko Hakubi (Tenchi Muyo!)

Midora (Toriko)