Sludge

Sludge is a boss in Golden Sun: Dark Dawn. It is a lizard-like monster that haunts the Phantasmal Bog and, by extension, Kolima Village.

As a boss
Fighting Sludge is required for the party to be able to navigate Kolima Forest, and thus progress to Talon Peak. In battle, Sludge will be accompanied by its Skull minions, and starts with a Haunt Skull and a Shield Skull. Sludge also has access to Curse Skulls. As the battle progresses, Sludge can call upon more Skulls to replace those that are destroyed. Sludge has a resistance to Mercury-based attacks and a weakness to Jupiter-based attacks.

Arsenal

 * Crush: A Mars-based Psynergy that attacks a single target with a power rating of 70 points. It consumes 7 PP.
 * Tail Slap: Sludge strikes up to 3 targets with its tail for a moderately strong attack.
 * Call Skull: Summons either a Curse, Haunt, or Shield Skull, with a limit of three Skulls at any one time
 * Healing: Sludge heals itself around 300 points of damage.

Defeating it will reward players with varying amounts of experience points and coins, dependent on how many Skulls were defeated. Also, Matthew can acquire the Crush Tusk after returning to Kolima.

Strategies
The battle with Sludge is fairly easy, relatively speaking, and is a great opportunity to gain experience. Most of Sludge's own attacks are fairly weak, though the player must be alert of the Skulls that accompany him. The Shield Skull can reduce the amount of damage Sludge takes, while the Curse and Haunt Skulls can inflict the Curse and Haunt statuses on the player. However, having a designated healer, such as Rief can reduce the negative effects of these abilities. Sludge and its Skull minions are all weak to Jupiter-based attacks. Thus, unleashing Jupiter Djinn and summoning Thor is an excellent offensive strategy.

Background and Story
Sludge was once an inhabitant of marshland located near Saha Town. After the Golden Sun event moved Kolima Village and Kolima Forest on top of the marshland, Sludge's home was destroyed. Sludge took to haunting the area underneath the Village, and placed a curse on the area surrounding Kolima Village. This not only caused Kolima Forest to become un-navigable, but sickened Kolima's Dream Tree, causing Kolima's Dream Leaves to cause nightmares.

Matthew and his party encounter Sludge while they are exploring the Bog after eating the cursed Dream Leaves. Sludge is seen using Crush to destroy parts of the pathway that Matthew is taking. After reaching the end of the Phantasmal Bog, Sludge attacks the group. Defeating Sludge reverses its curse, allowing the party to continue on their quest.