The below description is taken from LEGO.com.
Mr. Good And Evil
“Should I build or deconstruct today?”
Transformed by a laboratory accident, Mr. Good and Evil has been split into a good side and a bad side. Half of him wants to help people and solve problems, while the other half craves nothing but chaos and destruction.
Because both halves are in the same body, they’re constantly trying to sabotage each other. As a result, everything good that he tries to do ends up at least a little bit bad, and everything bad comes out a little bit good. According to the other Minifigures, it actually makes him a pretty decent neighbor…if you don’t mind all of the arguing!