A character replacement, also known as an Impostor!Sue, a Replacement!Sue, or a Doppelgänger!Sue, is what you have when a canon character is so badly out of character that mere possession or Suefluence no longer explains their behavior. When a character comes close to or reaches 100% OOC, they split into two characters: one character replacement, and one canon character. The canon falls or is forced into a plothole; the replacement takes over the character's role.