Klaww Skip is a major skip used in most categories to avoid fighting the Klaww boss, instead going directly to Mountain Pass, skipping the battle entirely.
Klaww Skip is done by first achieving Boulder Skip, and approaching the boss fight area. A short cutscene with Klaww will play. From here, you must climb back down, and walk over to Boggy Swamp. A checkpoint bug is then abused to deload Boggy Swamp, and respawn you directly at the last known checkpoint, the beginning of Mountain Pass.
The skip is demonstrated below by OutrageousJosh.