Put the gruntz on the proper pressure plate, when the checkpoint pyramids are down get rid of all gruntz except the sponge grunt. He picks up the resurrection spell and reads it. All puddlez change into gruntz. If one or more puddlez don't change you must have a grunt left anywhere in the game. Now hit the black one switch and cross the bridge towards the wingz. Don't pick up the warpstone piece yet! Fly to the left hand corner to trigger the red warp and hit the secret ? switch.

After you return from the secrets you pick the warpstone piece and give to the king

Congratulations you've completed this level and it wasn't easy!