Transform

Transform is a mechanic by which an item or skill turns into another item or skill without losing enchantments and without losing its "used" identity in relation to Confiscate Evidence, its relation to Slavemaster's Knout, or its relation with Sabotage. Transforming typically occurs when an item/skill turns into another item/skill it shares an item/skill slot with due to an effect internal to said item/skill, though it is also confirmed to take place due to the following:
 * Unstable Mutagen
 * Evolution Stone
 * Mystery Sprout turns into a plant item.
 * Ugly Duckling matures.
 * Core Crystal becomes a Magic Crystal.

Transforming can also occur through item combining with a consumed item that shares a slot with a produced item. (Item combining with consumed items that don't share a slot with a produced item will still result in an item that keeps the same non-Horcrux enchantments, but the produced item will not otherwise retain characteristics unique to transformations.)

A Marieke Doll transforming into another Marieke Doll due to its own effect won't trigger the Doll giving Wrath Of The Admin. However, transforming any Marieke Doll with Unstable Mutagen will trigger the Doll giving Wrath Of The Admin.

If Unstable Mutagen is used on a Horcrux, the transformed item retains the Horcrux enchantment, and Weakened Soul is not given.

An item chosen (but not yet sent) with Raven does not retain its "chosen" status when transformed due to Unstable Mutagen, but a chosen item does retain the status if transformed into an item sharing its item slot. Unlike Raven, Sabotage's "chosen" status is retained in either case. Evolution Stone relation needs testing.

If an item is transformed while visible in another inventory due to Sabotage, it can still be chosen successfully. The Smoking Mirror/Three-Eyed Raven relation needs testing.