Poofing?

Ange was watching the monster, making sure it stayed down and didn't get back up to attack them.. but then that word Steven uses draws her full attention instead. What does he even mean? Since when do any of these things 'poof'?

It's weird, but suddenly she feels much less concerned with the creature she just got rid of, like its constant present danger in her life is fading from her mind. She turns her back on the deflated thing, instead looking at Steven.

".. What do you mean?"