That's what I get for speed reading and posting before going into work.
Character Name: Diva Super Power/Mutation: Butterfly metamorphosis Reasoning: She likes taking naps and has made the butterfly pavilion roof her home. Therefore, I think it would be interesting if she crawled into/created a cocoon and hibernated until later in the day when she'll 'break out' mostly as herself but with a sensitivity towards light (more like a moth in this case) and therefore reduced vision. Also, (and I'm fine with doing without this, but I did read it in the wiki page) in order to unfurl her 'wings' she'll need to ingest blood.
Wiki Excerpt: After it emerges from its pupal stage, a butterfly cannot fly until the wings are unfolded. A newly emerged butterfly needs to spend some time inflating its wings with blood and letting them dry, during which time it is extremely vulnerable to predators. Some butterflies' wings may take up to three hours to dry while others take about one hour.
In terms of the metamorphosis itself, Diva already goes through something very like it where she creates a cocoon approximately 5 years of normal living. This cocoon is created to help protect her while she takes her 30 year nap after which she usually wakes up ravenous and operates on instinct until she readjusts to being awake (also aided, usually, by her ingestion of a chevaliers blood). So, this would in large part already be something Diva does but rather speed up and prompted by the gas effects.
Any last questions? Additional thoughts and/or limitations would of course be welcomed.