Creepy Crawly Forest was a pocket in Wonderland. As the name suggests, it was a dark forest filled with bugs. It was eventually cut from Wonderland.
It seems it may have been replaced by Spikes Peak: Chris Floyd, a content designer who left in late 2007, remembered Creepy Crawly Forest being part of Wonderland, but hadn't heard of Spikes Peak and thought it must have came after his time working on the game. Concept art of Brick Mesa also shows the Creepy Crawly Forest ruined castle wall where the border with Spikes Peak is on later Wonderland maps. the few object definitions that exist for Creepy Crawly Forest have internal IDs in the 1770s and from 1915 to 1920, while the Yeti object definition for Spikes Peak is much later, at 3204.
The concepts for the ruined castle wall re-use models from the Vanguard Outpost, which had already been scrapped.
Concept art by Dave Kang, dated 11/19/2007
A map of Wonderland from some point in 2008, notably lacking Creepy Crawly Forest
Brick Mesa concept art showing the ruined castle wall, indicating Creepy Crawly Forest may have been where Spikes Peak later was