When you talk to the inn manager in Nimbus Land, after you say you want to sleep, you can plunk down an additional 30(?) coins to sleep on the Dream Pillow that night. You get funny random dreams, but you only get an item if you get the dream that has Toad saying he's really a monster. Then you wake up and Toad's there. Mario gets all freaked out, and Toad gives him an ultra-rare Red Esscence which is used in battle on one person to gain 3 turns of invincibility! The only other place you can find Red Esscences are in some invisible ? blocks.