Pokémon Ruby Version, Sapphire Version, and Emerald Version - Last move used
Whenever a Pokémon uses an attack, even if it fails, the game sets a variable to that move at the end of that Pokémon’s attack segment. This variable is called the "last move used" and each Pokémon has a "last move used". The "last move used" is set even on the first attack segment of a two-turn attack.
The "last move used" is set to an invalid identifier for a move if the move used is Mimic, Sketch, or Transform; if the move can’t be used because it has zero PP; or if the move is prevented from being used.
The "last move used" is set even on the first attack segment of a two-turn attack.
This variable doesn’t change when the Bag command is used to use an item, at the end of any turn in which the Pokémon leaves the battle with Baton Pass, or when the Run command is used and running is unsuccessful. If the attack is taken with Snatch, the variable is only set for the attack’s original user. If the attack is taken with Magic Coat, the variable is only set for Pokémon that actually use the attack. The variable is reset when the Pokémon leaves the battle,.
The use of Pursuit as a Pokémon is about to switch doesn’t count as the "last move used".
Sketch uses a different version of the "last move used". The differences are that this variable doesn’t change on the first attack segment of a two-turn attack or when a move is prevented from being used by a Pokémon; that at the end of any turn in which a Pokémon at that position leaves the battle using Baton Pass, the variable is set to the move that Pokémon chose for use that turn; and that the variable changes to a move even if it can’t be used because it has zero PP.