For the Halloween seasons of 2019 and 2021, a temporary Halloween troop called the Royal Ghost was added.
Strategy
Offensive:
If they are positioned close to the exterior of the base, their extremely high DPS allows them to snipe defensive buildings.
Like Sneaky Goblins, Royal Ghosts do not activate Clan Castles when they are invisible. Using a Royal Ghost or two to destroy the Clan Castle can stop defending Clan Castle troops from leaving it and entering the conflict if the Clan Castle is exposed or otherwise easily accessible.
Clan castles are destroyed by using Royal Ghosts.
Defensive:
Even though they are invisible, Royal Ghosts can be readily stopped by traps, especially Giant Bombs or Spring Traps, despite their high damage.
Because Royal Ghosts remain invisible for an extended period of time, they can assault any spawn zone inside the village walls and do damage to nearby units without facing any resistance.