Well, I actually just got the one that came out of the Final Unity game box.
Apparently the battery was dead, so after I found a suitably tiny screwdriver, I removed the back to get at the battery. Maybe there's some trick to it, or it's not supposed to ever be removed, but I found it difficult to pry the battery out of its little niche. But I did that, and placed a new battery and it immediately started functioning again.
So, this might be a dumb question, but is one supposed to just leave it running endlessly until the battery drains? I can't see a way to activate/deactivate it short of unscrewing the back and taking the battery out again. How long is this battery supposed to last playing this animation?
Would appreciate any insight. Thanks.