A: To refresh, in Fantasy Fluxx, the Magic Sword Keeper has the ability to move one Creeper away from you to another player. Evil is an Attaching Creeper which could be attached to the Magic Sword. Evil does not impair its Keeper, however (cause it to lose its special ability), so the Magic Sword could still be used to “banish” Evil. Since Attaching Creepers and the Keeper they’re attached to stay together unless otherwise noted, the Magic Sword would end being used to banish itself. Think of this as the player looking at the sword, realizing it’s evil, and yeeting it away from themselves.

Contrast this with the behavior of the Laser Sword in Star Fluxx, which can be used to destroy a Creeper. The Laser Sword can not destroy the Creeper attached to itself, because that would mean destroying itself. Picture the player picking up a laser sword and attempting to use the laser sword to strike itself. It’s just not possible.