Sleepy Voice

Once during your turn (before your attack), you may flip a coin. If heads, your opponent's Active Pokémon is now Asleep. If you use this Ability, your turn ends.

It's always practicing its singing because it wants to improve. Even when it's asleep, it keeps singing in its dreams!

Igglybuff

Cosmic Eclipse

Ability — Sleepy Voice
 Once during your turn (before your attack), you may flip a coin. If heads, your opponent's Active Pokémon is now Asleep. If you use this Ability, your turn ends.