From Homestar Runner Wiki
The Goblin is a green, armless creature who appears in Halloween episodes. An organ tune plays when he shows up, and he does a short dance. The movement of his feet when dancing is very similar to Leg Movement #1 in the Dancin' Bubs game. The Goblin seems to be the only inhabitant of Free Country, USA who has visible ears.
The Goblin was created when Homestar Runner started telling a pass-along Halloween story in Homestarloween Party. He seems to make guest appearances in almost all Halloween episodes (the only major Halloween specials he has not appeared in so far are The House That Gave Sucky Treats, Halloween Fairstival, and Doomy Tales of the Macabre).
By virtue of Bubs's addition to the pass-along story, he is also the owner of a '73 Gremlin. He's found hanging out under it in the Spooky Woods in Where's The Cheat?. Rocoulm, who claims the Goblin has "serious problems", refuses to entertain him.
In Most in the Graveyard, Homestar is convinced that finding the Goblin at midnight will allow the Goblin to spin their candy into gold. The Goblin also saves Homestar and Pom Pom from the Carnivorous Undead Sheep and dances to a much funkier beat.
 Character Evolution
|Concept art of The Goblin||????||Sketch Book 22-11-04||N/A|
|First design of The Goblin||2000||Toons from Homestarloween Party to Happy Hallow-day; Main Page 7||N/A|
|Second Goblin||2008||Most in the Graveyard||More advanced shading and more detailed eyes, his feet are a different shape and he is now animated more smoothly. His body is a different shape, his eyes and head are smaller and his outlines are thicker and darker. His mouth is slanted at the end by his ear.|