Beyond Time: Lavos
Time-Error: (Any time the pocket dimension comes into contact with the timeline, the time* of the pocket dimension that appears is determined by the time-error of an existing gate in the timeline.)
Nature & Analysis
Lavos displays some strange behavior. If the travelers defeat the shell and warp into the past, the shell is still defeated. A strange blue aura surrounds Lavos during the Ocean Palace disaster and the final battle. Lavos' Core is able to open time warps to different eras. Lavos also appears to have knowledge of the future; during the final battle it emulate the fighting techniques of Guardian, which exists in 2300 AD. A possible explanation is that Lavos exists within a pocket dimension, or "time bubble," which transcends time.
When Lavos arrived on earth in 65 million BC, it created a pocket dimension separate from normal space time, existing on the time-error axis. A wormhole connects the pocket dimension to every time period.
Lavos is not actually physically present within the earth. The wormhole aperture is located at the earth's core, giving Lavos access to the planet's energy and lifeforms. During the Day of Lavos or the Ocean Palace disaster, the wormhole ascends to the surface, causing a dimensional disturbance. The wormhole offers an uninterrupted view of the pocket dimension, creating the illusion of Lavos' presence.
If one approaches Lavos, and passes through the wormhole, the interior of the pocket dimension has the appearance of the blue aura which surrounds Lavos. During the Ocean Palace Disaster, Queen Zeal, Magus and the others warp into the pocket dimension. During the final battle, Crono battles Lavos in the pocket dimension.
Lavos' core is able to open time warps to different times, because it is connected to those eras through the wormhole. The aperture of the wormhole gives a distorted view of the time period being accessed. Lavos is also able to survey the entire timeline and would have knowledge of, for example, the Guardian's fighting style from 2300 AD.
After* Lavos dies, the pocket dimension no longer connects to space-time, but the past* Lavos still exists, and would be theoretically accessible if a time traveler accessed it from an earlier* time-error then that at which Lavos was defeated, but it is generally not possible to travel to a lower time-error.
This then raises the question of why Lavos chose to ascend in 1999 AD. if it had the ability to ascend at any time. The reason for this can be inferred from Lavos' original purpose.
"Now I understand... It lives on a planet for as long as possible, stealing away the most vital resources... It combined the DNA it found here with its own, and gave birth to those creatures up on Death Peak."
"This was Lavos's goal...! Using the DNA of every organism... And achieving the ultimate in evolution!"
It is likely that Lavos determined that 1999 AD was the best balance of collecting as much DNA as possible and having as low a chance as possible of the inhabitants defeating him.
It's worth noting how the timeline would appear to Lavos. When he's in the core of the planet at first, he would see a timeline in which Zeal taps into his energy and uses it for their own purposes. He then decided to stop this, so interfered and destroyed Zeal. When he went back into the planet, he saw the timeline progressing from that point, with Zeal being destroyed and the populace eventually advancing beyond where they were in 1999 AD. (he sees a regular future rather than the ruined one). He then decides that 1999 AD. is the best time to arise, so he does so. In the "Lavos Timeline," he rains destruction on the world, exits his pocket dimension, and starts producing offspring. The short period between when Lavos rises and when he exits his pocket dimension (when Crono's party takes him on) is the only time when the wormhole can connect to the ruined future.
Lavos - Lavos is a being of godly power who crashed into earth in 65,000,000 BC and laid waste to it in 1999 AD. His purpose was to harvest the DNA of all lifeforms on earth in order to create even more powerful offspring. In order to improve this process, he artificially accelerated the evolution of humans.
Analysis - The origin of Lavos is unknown. He may be unique, or one of many. Theories include:
1) Lavos is the result of a lot of natural evolution which resulted in this "monster."
2) Lavos (or one of his ancestors) was a biological superweapon gone wrong (think Deus from Xenogears).
From: Beyond Time