There is some funny stuff going on – if you happen to see some oddly-colored mounts, steer clear of them, they maybe soon going poof, if they haven’t already. Some of these may have a shadow shade to them, others red or green.
From the UO Producer, this was posted on UOHerald.com:
We would like to bust a recent myth about transfers from Test Center.
There are two shard types that players may not transfer “from” or “to”: Siege and Test Centers.
Character transfer is not enabled for these shard types, nor will it be implemented.
So why are you seeing strange hues on some pets? During the recent updates and patches to the game, some content we made available for testing, made its way onto production shards. We identified the problem immediately and put in a fix during maintenance to prohibit more “illegal” hues to make their way into the game. In addition, all changes were reverted … but not before some content made its way onto live shards.
Right now we have monitoring in place to identify what items and hues were available before the update, and which were made available to those who took the opportunity to exploit the changes.
Know that for those who have taken the opportunity to exploit, those hues will also be reverted to their original state