Climb the Giant
Drizzt can climb right up one side of huge foes and tumble down the other to land like a cat.
Grandmaster Training 840 gp
Power Encounter (Move Action)
Requirement: You must be adjacent to a creature whose size category is larger than yours.
Effect: You shift up to 5 squares to a square adjacent to the larger creature. During the shift, you can enter the creature's space.
Published in Neverwinter Campaign Setting, page(s) 150.