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 effects like Confiscate Evidence or its relation to Slavemaster's Knout. 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.
 * Turkey is roasted.
 * Roasted Turkey turns into a Wishbone.
 * Dragon Egg hatches.
 * Ugly Duckling matures.
 * Chameleon/Hidden Chameleon transform into one another.
 * Core Crystal becomes a Magic Crystal.
 * A Mystery Seed transforms into Tainted Rose or Four-Leaf Clover.

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.