Spooky Woods
From Homestar Runner Wiki
The Spooky Woods is the creepy forest where the Halloween cartoons take place and had been seen only at night until the 2006 Halloween cartoon Happy Hallow-day.
They seem to be the Halloween variant of The Field, with seasonal foliage consisting mainly of multiple instances of one or two Spooky Tree designs in various sizes, orientations, and colors. (Similar trees are found in the Punkin Patch, which may be the Old-Timey version of the Spooky Forest.) In the daylight, the forest is much less forbidding, as seen in Happy Hallow-day.
The forest features a creepy cliff, and is inhabited by The Goblin.