Track 2 on Tool's 2001 album Lateralus. An instrumental track that seems to be a prelude to The Patient more than anything.
About a minute long, and featuring only the guitar, the song still seems to have a strong eastern feel to it. It's not difficult to imagine it being played on a sitar.
"Æon Blue" is the name of a chatroom on the official Tool site (http://www.toolband.com/chat/room2.html). Eon is apparantly also the name of guitarist Adam Jones's dog. Taken from a news post at the official site dated 2/19/01:
For those of you who have been asking about Eon...
Adam's 190 pound great dane was diagnosed with osteosarcoma 3 weeks ago. After a number of tests, the doctor's decided to amputate his leg. He will begin chemotherapy next week.
There is no real cure for the disease, because the malignant cells begin spreading throughout the body before the tumor appears. With the amputation and treatment there is a strong chance that his life will be extended for years. Keep your fingers crossed.