Drool  is a Goblin with shape-changing abilities. He is first encountered when the Ghostbusters investigated a traveling circus in the Poconos. When they see Drool, they think that he is the ghost they had to bust. Even when it is made clear to them that Drool isn't a threat, they still don't choose to believe it.
Drool encountered Madame LaFarge's Wondrous and Amazing Traveling Sideshow and started tagging along wherever they went. LaFarge eventually let him take part in the performances.  He was billed as "Drool, the Dog-Faced Goblin." As part of his performance, Drool would leap onto stage and pretend to attack a performer named Little Egypt.
A few years later, the Ghostbusters encountered a shape-changing phantom they failed to bust a week ago and took the opportunity to trap it, Drool sacrificed himself by biting the phantom and getting trapped along with it. If he let go, several people would have been hurt by the phantom.
Drool is very friendly and is likely very brave, as shown when he let himself get trapped so the Ghostbusters would succeed in trapping the shape-shifting phantom. This contradicts the general nature of a Goblin. 
It should be worth noting that even though Drool "talks" in a series of weird grunts and noises, Madame LaFarge, the woman whom runs the sideshow seems to be able to understand what the goblin is saying.
After some P.K.E. readings are taken, Drool is referred to as a "Free Standing Four Footed Four Armed Garden Variety Green Goblin."  However, he isn't green in the episode.
Drool can assume a variety of forms, such as a spider, a skeletal version of himself, a winged version of himself, and a black grub-like worm.
Ray Stantz explains that they can't free Drool because when two ghosts are captured in a single trap, their molecules mix and they can't be separated.  Other episodes contradict this by showing more than one ghost captured in a single trap to still be separate entities when they are put into the Containment Unit. However, since Drool bit the Metamorph before the two were trapped, it is possible that Ray meant that if more than one ghost was caught in the same trap and they made any form of contact with each other, they would merge into a single entity.
- On page six of Ghostbusters Issue #3, Droll makes a non-canon cameo. He is in a garbage can in the garage bay of the Firehouse.
- On the subscription cover of Ghostbusters Volume 2 Issue #13, Drool makes a non-canon cameo.
- In Ghostbusters Annual 2017, on page 44, the Queens Class 5 is visually based on Drool.
- "Drool, the Dog Faced Goblin"
- "The Grundel"
- NOW Comics Volume 1 Issue 26
- ↑ Winston Zeddemore (2009). The Real Ghostbusters- Drool, the Dog Faced Goblin (1987) (DVD ts. 2:13-2:19). Time Life Entertainment. Winston says: "See the Amazing Two-Headed Rabbit, a living Uniforn, a real Mermaid and Drool, the Dog-Faced Goblin?!"
- ↑ Madame LaFarge (2009). The Real Ghostbusters- Drool, the Dog Faced Goblin (1987) (DVD ts. 4:47-4:52). Time Life Entertainment. Madame LaFarge says: "Drool adopted us a couple of years ago and he's been tagging along ever sense. I finally put him in the show."
- ↑ Egon Spengler (2009).The Real Ghostbusters- "Drool, the Dog Faced Goblin" (1987) (DVD ts. 06:23-06:27). Time Life Entertainment. Egon says: "Harmless and Goblin are mutually exclusive terms."
- ↑ Egon Spengler (2009). The Real Ghostbusters- Drool, the Dog Faced Goblin (1987) (DVD ts. 3:32-3:36). Time Life Entertainment. Egon says: "I think we got a Free Standing Four Footed Four Armed Garden Variety Green Goblin here."
- ↑ Ray Stantz (2009).The Real Ghostbusters- "Drool, the Dog Faced Goblin" (1987) (DVD ts. 21:00-21:10). Time Life Entertainment. Ray says: "When you trap two ghosts at the same time, their molecules mix. You can't separate them."