- "Isaac, there’s something big on the hull of the ship, directly above the Comms Array. Something organic."
- —Kendra Daniels
The Slug is an exceedingly large Necromorph and the boss of the eighth level of the game Dead Space. The Slug was blocking the blast doors on the USG Ishimura, which were needed to broadcast a futile message to warn the USM Valor to not open the escape pod they had retrieved because of a Slasher inside.
The Slug had to be fought using one of the Ishimura's anti-asteroid cannons, specifically ADS Cannon 48. During the fight, it would use its five tentacles to hurl objects at the tower, with each tentacle having a weak point appearing as a bulbous yellow mass close to the slug's body.
Defeating the Slug required the destruction of all five tentacles - while at the same time using the cannons to destroy the incoming debris thrown by the Slug.
Immediately following the Slug's demise, it releases its grip on the Ishimura and begins floating off into space. At which point Kendra is able to broadcast a warning to the USM Valor, telling them not to open the escape pod they retrieved. The return broadcast shows a Marine of the Valor being slain by a Necromorph, indicating that they lost the battle. The Valor then crashes into the Ishimura, causing considerable damage.
The Slug was originally thought to have arrived on the ship after the initial infection, due to the fact that ADS Cannon 48 would have engaged it. However, Dead Space: Extraction proves this point incorrect; as Nathan McNeill disabled this particular ADS cannon (and possibly the system itself), the cannon would have been unable to fire at anything until Isaac came to manually reactivate it.
- The Slug is initially placid and won't attack unless fired at. Only then does it rear up its tentacles to tear the ship apart, exposing their weak spots in the form of yellow bulbous masses as it hurls chunks of the ship's hull and explosive gas canisters at the ADS Cannon tower.
- Fire should be diverted to any explosive gas tanks the Slug hurls at the cannon, since they do more damage to the tower than hull debris.
- Each of the Slug's tentacles pauses briefly before throwing the object it's holding. Shooting the tentacle's weak spot at that moment causes it to flail madly and hurl the object in a random direction, generally not towards the tower.
- If you have a good aim, a tentacle can be taken down quickly by firing both ADS turrets at the weak spot at once. Don't keep this up for an extended period of time, however, or the turret will overheat and become unusable for a short period of time.
- Another good tactic is wait for the tentacles to reach into the ship to grab an object to throw at you. Once it reaches, shoot the orange bulb on that arm. This will cause the arm to leave the object where it is and flail madly.
The Slug doesn’t have a direct hit to finish Isaac off; but when the hull integrity reaches 0%, the turret in which Isaac is violently explodes, sending Isaac flying out of the turret seat (although in one piece). Isaac lives for a few seconds after; he raises his hand as if he would be trying to reach something, then dies because of the exposure to the massive fire caused by the explosion.
- The Slug seems to have some kind of face or mouth, however it is very hard to see due to the cannon blocking The Slug's front end.
- Pieces of the Slug can be seen in the Comms Array due to some of its bio-mass hanging from the blast doors on the ceiling of the array.
- The Slug is actually far easier than the first ADS cannon section in Chapter 4. The debris that the Slug throws do more damage, but are much larger and easier to hit. Also, there aren't that many projectiles during the fight, as the actual range of the window for aiming is smaller to accommodate this. Also, the cannon never overheats unless both triggers are used when firing. The ADS Cannon used during this part also has a full 100 hitpoints compared to the damaged one used in Chapter 4.
- It's possible the Slug could be a mutated off-shoot of the Spider boss in the prequel Dead Space Extraction or, seeing as Dead Space picks up only a few hours after Extraction, the Slug could very well be a wounded Spider clinging onto the Ishimura's hull.
- It is also possible that The Slug is in actual fact the full view of the body of The Leviathan, as the Leviathan's full body is never seen, and is stated to come from space. This, however, is most likely false as the Leviathan was in Food storage, while the Slug is over the Communications Array.
- The Leviathan could have moved from Food Storage to the Comms Array using its large tentacles, but again this is highly unlikely, as Kendra states that it is dead.
- If you return to the ADS Cannon Pit later, you can strangely still see the Slug through the gaps in the now sealed blast shield/viewport. A bit odd, after it was seen blasted into space by the ADS Cannon, however this is likely just a slight oversight by the developers.
- Even if it isn't hit directly with a shot upon first starting the fight, it still attacks the tower as if it was hit.
- There is a small glitch in which after you destroy the Slug and the USM Valor crashes into the Ishimura, and Isaac is thrown out of the ADS Cannon seat, before the cutscene triggers, sometimes there are additional explosions that cause Isaac to flop around on the floor.