My team is looking for a technical term which may or may not exist.

We are trying to describe an environment, such as a database, which has been built up over time with little or documentation about the change process that has gone into it. Generally these are legacy systems who's original developers have long since moved on and they are in such a tangled and unmanageable state that the only way to recreate the environment, say for testing purposes, is to copy it and do your best guess at re-configuring it for its new purpose.

So far the best term we have come up with is Amnesic, such as "setting up the new test environment is going to be a challenge because it is an amnesic db." However, we are still not quite happy with the term and were wondering if a better and/or more accepted term for this situation exists.