If u play online ull see it often, use a mushroom near the cliff end(at the beginning of the cave, near the fence gap) and u will warp near wuhu castle!(the other way is to pick up enough speed to hit the water, though this is much harder.)
Haha, well, just a polite post here to let you know that everyone here is VERY well aware of this glitch. In fact, it causes a lot of heated debates too, so due to this topic not exactly contributing anything else (and just being a big cage for people to fight in) I'm going to close it. No hard feelings, just making sure nobody's feathers get ruffled.