Gobber

"Their appetite is...ah...formidable. With stomachs that lack physical boundaries, they won't hesitate to devour everything around them! Be wary of the puddles of...goo."— E. Gadd , Luigi's Mansion 2

The Gobber is a ghost whose first apperence was in Luigi's Mansion: Dark Moon, in the level "B-1 "A Job For a Plumber". They have 100 HP and their highest observed weight is 45w. The Gobber's main attack is spitting goo out of his mouth at Luigi but it can also, if Luigi gets close enough, resort to using a somewhat bizarre melee attack in the form of slamming into Luigi with its large gut.

If Luigi steps on a puddle of goo created if the Gobber spits goo and misses, he will slip and lose hold of any ghosts he is currently vacuuming up. If a goo shot lands directly on Luigi, he will take 10 HP of damage and slip as well, losing hold of any ghosts that are being captured.

Strategy (by Arouteous Fawful)
When capturing a Gobber, strafe around in a circle around it. This will minimize the chance of getting hit by its goo and it will also grant you some degree of avoidance from other ghosts. If facing a Gobber with multiple support ghosts, tackle the support ghosts first as a Gobber will always stay in one spot.

When fighting multiple Gobbers, start vacuuming one of them until the other one spits out goo in such a way that you can't dodge it without the risk of getting hit by something else. When that happens, stop damaging the first one and move over to the other one until the aforementioned scenario happens again, then switch back and forth between the two as the situation demands until they are both defeated.

Trivia

 * Gobbers are similar to Mr. Luggs because he is a fat ghost from Luigi's Mansion who loves to eat everything.
 * Gobbers wre thought to be a reference to Homer Simpson who is from the 25 year old TV Show The Simpsons because they are fat and yellow. But this has never been confirmed by Nintendo and is most likely a fan theory.