There's this guy--his name's Hawkmoth--who uses his powers to transform people into something different. He gives them powers so they can do a lot of damage in his place.

[Ladybug's hands fiddle idly with her yoyo, mouth pulled down into a slight frown.]

He takes advantage of people's emotions and twists them. All those victims he takes over are just...having a bad day and don't even remember what happened while they were in their other state.