Bottom's "translation" into an ass is a kind of emblem for all of the transformations that occur in the play. What are these transformations?
There are several transformations in the play A Midsummer Night's Dream by William Shakespeare.
Besides Nick Bottom's transformation into an "ass," and back again, we also see transformations in terms of the relationships of the characters.
Hippolyta is the Queen of the Amazons, a war-like race of women. She has been "won" by Theseus (the Duke of Athens) in battle, but now he would like to woo and win her in love. She watches how he handles the affairs of those around him, in particular the affairs that deal with men and women. While Hippolyta is critical of, for instance, Bottom and his players, Theseus shows what a fine leader he is by extending his gracious acceptance for all regardless of their social status. Perhaps this is the reason that by the play's end, Hippolyta has softened somewhat towards Theseus, seemingly more willing to accept him than before.
Another transformation can be seen in the marriage between Oberon and Titania, King and Queen of the Fairies, who have been fighting over a changeling child, born to a friend of Titania who has since died. One of the major conflicts of the story is found in the opposition between the two, which Titania explains (and the Elizabethan audience would have believed) that when there is an imbalance in the fairy world, it causes an imbalance in the human world. (This theme is also seen in other of Shakespeare's works, including Macbeth.) At the conclusion of the play, Titania relents, won over by her love of her husband and his obvious love for her, and it would seem there is a mutual agreement to "share" the company of the child.
We see a metamorphosis with the Athenian lovers. At the start, Hermia and Lysander are in love. Demetrius wants to force Hermia into an unwanted marriage to him, while Helena has been spurned by Demetrius, but still adores him. As the plot of the play moves forward, the couples fall out of love, in love, and out again, etc., until all are happily joined. (Demetrius' transformation is brought on with some help from Oberon and Puck, and the use of a magic potion: he loves Helena, and they marry at the end, with the others.)
A final transition takes place with the craftsmen-turned-actors who hope to perform for the Duke's wedding. If their play is chosen as entertainment for the event, they will have it made as actors. In other words, if the Duke chooses them, their reputation as one of the finest acting troupes in the land will be solidified.
Of course, these actors are not remarkable, in the least, but very entertaining. They are thrilled to find they have been selected by the Duke. And while they fumble along with egos and barely noticeable theatrical skills, as well as interference from the fairy-folk, they eventually give a relatively good presentation of their play. And Bottom, at the end, excels beyond his own expectations, providing a beautifully rendered death scene that touches the audience. The actors, especially Bottom, are transformed.
The transformations in the play involve humans and fairies; some are permanent, while others are temporary. As always, Shakespeare shows a keen insight into the human character, and displays this in the play, as well as his flair for comedy.