Air Date: September 11, 2010
To get this ending you need to fight Lavos after you get Robo in your party. For me this happens right after you gate jump from the proto dome from the future and end up at the end of time for the first time. Then you can use the bucket to go directly to Lavos once you have finished speaking with the guru of time.
The ending itself involves watching the credits while a Nu, Kawala, and frog dancing around and chase each other on the side of the screen.