Create an air enemy, and give it the sprites you want to make it appear as though it's walking on a wall. Create wall arrows or create a timeline that controls it's movements. If you want it to jump from wall to wall, all you need to do is just change it from an enemy to a projectile and choose the projectile direction towards the wall on the opposite side. Then make it so that it spawns another enemy that will basically mirror the previous enemy's movements.
