In Sailor Moon a butterfly motif is heavily featured in the titular heroine's "Crisis Make Up!" Transformation Sequence which sees her power up from Sailor Moon into Super Sailor Moon in the third season Sailor Moon S. This is not only touches on this trope but also draws on the way the Butterfly of Death and Rebirth trope is used elsewhere in the season, a particularly evocative version shows up using the power of the Sailor Soldiers themselves rather than via the usual Holy Grail Transformation Trinket that was in hands of the enemies in the penultimate episode of the season which is given it's own animation.
Evoked in a Marvel Comics story of The Inhumans, with one Inhuman petitioning to be exposed (re-exposed) to the mutagenic Terrigen Mists mainly because she's ugly and hoping for a better genetic draw. She emerges as a butterfly woman.
Vic Sage'sFamous Last Words in 52 invoke this symbolism of butterflies. They are addressed to Renee and foreshadow her transformation into the new Question.
In the book/movie The Silence of the Lambs Jame Gumb keeps butterflies or moths, and they seem to symbolize his desire to transform into a woman.
The hero of Kung Fu Hustle gets entirely wrapped in bandages like a cocoon, which he discards as a shell, his Chi finally unblocked and his destiny awaiting. During this transformation, we are briefly treated to the imagry of a butterfly emerging from a cocoon to drive the point home.
The caterpillar in Alice in Wonderland can be seen to serve this sort of symbolic function. For instance, at the end of the 2010 film, Alice has been somewhat transformed by her experiences in Wonderland, and this is symbolized by the caterpillar (called Absolem in this adapation) appearing on her shoulders in the form of a butterfly and doing a Fly-at-the-Camera Ending.
The I Am Legend remake feature the motif of a butterfly quite often. In the released film, it doesn't amount to anything; however, in the original ending, it represented that that the Dayseekers weren't mindless, evil zombies, but sentient beings that had transformed into a better forms than the old-fashioned humans. Keep in mind that the "better" form is eye of the beholder.
In Gene Stratton Porter's Freckles, Freckles watches in wonder as a Luna moth comes from its cocoon and feels deeply frustrated at his ignorance at what it is, though he knows it's not a butterfly. This causes him to ponder his ignorance, until it dawns on him that he could find out these things.
In Terry Pratchett's Discworld novel Making Money, Cosmo Lavish uses a caterpillar becoming a butterfly as a symbol of his own planned transformation. His sister Pucci tells him that what actually happens is a caterpillar dies and a butterfly grows out of the remains.
The Animorphs book "The Departure" heavily feature the theme of a caterpillar, and later a butterfly. It is not a coincidence that this is where Cassie meets a surprisingly sympathetic yeerk, one willing to give up her host body. This, along with Cassie's continued realisation that the world isn't as black and white as she thought, signifies change.
In Sarah Addison Allen's The Girl Who Chased The Moon, when Emily's wallpaper changed for the first time, it changes to butterflies. They seemed trapped and wanting to escape. She had just learned things about the town that make it hard for her to stay. Though neither the butterflies nor she manage to get away.
In Babylon 5, Delenn uses a butterfly-like cocoon to transform into a half-human half-minbari. During the transformation, the security team exploited the trope by telling the traitor that it she became beautiful as she left the cocoon, as if she was a butterfly with wings.
A moth emerging from its cocoon was used in an early episode of LOST as a metaphor for Charlie weaning himself off drugs. Made very explicit by Locke.
In the "Bridezilla" episode of ABC's What Would You Do?, a woman asks her bridesmaids to wear purple dresses to which she has appended butterfly wings, as a symbol of transformation through her marriage.
In Doctor Who, the Second Doctor compared his regeneration to a renewal like a butterfly emerging from its chrysalis. Which is why the ring no longer fits.
Doctor: I'd like to see a butterfly fit into its chrysalis case after it's spread its wings! Polly: Then you did change! Doctor: Life depends on change and renewal I've been renewed. It's part of the TARDIS. Without it, I couldn't survive. Polly to Ben: It's a very different Doctor, then.
Marilyn Manson's Antichrist Superstar album is a narrative about a child's transformation into the antichrist (/a controversial rock star). The song cycle is broken into three parts according to the life cycle of an insect, and the album art depicts him in stylised versions of all three stages, including one with a set of wings.
Using a dragonfly rather than a butterfly, the Ego Likeness album Dragonfly has a theme of personal rebirth and the cover art◊ depicts the eponymous insect.
Player's Handbook. The Polymorph Other spell changed a creature into another type of creature. Its material component was a caterpillar cocoon.
Oriental Adventures supplement. The Force Shapechange spell caused shapechangers to shift to their alternate form. The spell's material component was a butterfly cocoon.
In Charlie and the Chocolate Factory (the 2013 West End musical), Willy Wonka has an I Am What I Am song, "Simply Second Nature", in which he explains his inborn need to create beautiful — if strange to some — things. At one point, a sudden wave of his cane reveals a butterfly perched upon it, which continues this adaptation's running motif of humble things that contain/conceal great beauty and possibility (tying in to the Central Theme of the transformative power of imagination).
In the Persona series, the golden butterfly is symbolic of Philemon, the diety that allows the heroes to tap into their Personas. According to Word of God, in the later games in the series he actually appears as a blue butterfly with an implied similar, if lesser, function, although neither the characters nor any narrator identifies him.
This is part of Morph Moth's gimmick in Mega Man X2. He starts the fight in a cacoon suspended on a thread, and after taking enough damage he, appropriately enough, metamorphosizes into a fully a fully grown robot moth.
At the end of Bambi II, Bambi has lost his spots, his antlers are starting to grow and most importantly, he has an improved relationship with his father. A butterfly lands on the entwined sprouts growing nearby.