From the Super Mario Wiki
Slammers are ghosts appearing in Luigi's Mansion: Dark Moon. They are quite large and resemble Blue Twirlers. Slammers appear usually mixed in groups of Greenies, but they are also seen in groups of two to three. Slammers are slow-moving ghosts. They are first encountered in Gloomy Manor in the mission "A-2: Gear Up". Slammers have 30 HP. Although they are sometimes allied with Greenies, they also seem to have some degree of violence toward each other, seen when a Slammer tried to chew on a Greenie just before being calmed by the reformed Dark Moon.
Unlike other ghosts, Slammers (and other variants) have only a single sound effect when viewed in the Vault.
Slammers are equal to Blue Twirlers when it comes to abilities. Slammers have the ability to create a shockwave in front of them by clapping their hands together. They are also able to pull objects such as gears right through walls. As seen in the Old Clockworks, they are able to travel underneath sand without revealing their red body.
Ghost Container description
Dark Moon Quest
Luigi's Mansion: Dark Moon Website
"Watch out! These heavy hitting brutes are so rough and tough that when they clap their hands, it creates a crushing energy wave."
Names in other languages