The Werewolf's Cave, located beyond the Honey Bee Gate, is home to the Werewolf and two spider-like Cave Monsters. There is a Gold Egg at the end of the cave.
To get the Gold Egg, gain all the speed you can via hats, guards, Bear Morph, and stacks of Haste and/or Haste+, and then make a run for it, jumping the whole way to avoid getting killed. If you encounter the glitch where enemies don't spawn, you can easily stroll into the cave and get the Gold Egg without preparation.