This plant wins the ugly prize, only a true Costus lover will buy this plant. I ordered rhizomes from Jorg Pein's Heliconia Paradise in Thailand where it was listed as Costus speciosus. When the plant grew and flowered it was obviously not that species but I don't know for sure what it is. It has the fibrous margins to the bracts like Costus pulverulenus but the flowers are the C. scaber type and in a color like Mark Collins' 'Belize Yellow'. So it may have just been an odd hybrid seedling.
I send most of my collections to my friend John Mood to grow in Hawaii, including this one. In 2010 I was visiting his place and there was this plant, looking like the photos below. All I could think of is that the "dark side" had taken this plant - thus the name 'Darth Vader'. So if you are just a little weird, you might want to add this to your collection.