What Have I Done?

This.

After somebody commits an action, they're not guaranteed to be proud of what they've done. They might look at the aftermath of their acts and feel a deep guilt after doing so. This could have been murdering many people, pranking somebody, destroying a city or town, or arguing with them and saying something that makes them run away in tears. If an antagonist plays this UnTrash, it's often because they just had a Change Of Heart after seeing what they've done to other people and, if this UnTrash is powerful enough, will lead to them vowing to end their evil ways and join the forces of good.