Transform

Type

Normal

Gen.

Power

???

Priority

Effect Summary

User becomes a copy of the target until it leaves battle.

Detailed Effect

Transform causes the user to become a copy of the target (copying image and moves).
Transform bypasses accuracy checks to always hit, unless the target is in the semi-invulnerable turn of a move such as Dig or Fly.
It is not affected by type immunity.
Transform fails against:

Shadow -type Pokémon
Pokémon that are protected by Crafty Shield
if the user is disguised by Illusion (not in Gen 1)
if the the target is disguised by Illusion (not in Gen 1-4)
targets that are behind a Substitute (not in Gen 1-4)
Pokémon with the ability Good as Gold

A transformation can not be passed by Baton Pass and the user will return to its original state after switching out, fainting or when the battle ends.
Transform also copies some of the traits of the Pokémon including:

Species
Appearanace
Types
All base stats , except HP
Current stat changes
Current moves
Height and weight
Catch Rate (only in Gen 3-4)
EV-yield and base experience (not in Gen 1-2)
Ability
Cry sound (not in Gen 1-3)
Gender (not in Gen 2-4)

Description

GS C	The user assumes the foe's guise.
RS E	Alters the user’s cells to become a copy of the foe.
FRLG	The user transforms into a copy of the foe with even the same move set.
DP HGSS PL	The user transforms into a copy of the foe right down to having the same move set.
COL B2W2 XY ORAS SM USUM LGPLGE SWSH	The user transforms into a copy of the target right down to having the same move set.