Metronome is a move-calling Normal-type move.
Metronome randomly selects a move, but not itself and a few others listed below, and fully executes the attack.
An attack called by Metronome in this way counts as the last move used. Metronome takes on that move's targeting. A Pokémon will be able to use a move that is disabled if called via Metronome.
Because Metronome has normal move priority, a move with higher or lower priority may be executed other than when it normally would. For instance, Metronome may cause Quick Attack to be used after a normal priority move or Vital Throw to be used before a normal priority move.
Move that cannot be called by Metronome
Pokémon that learn Metronome
By leveling up