Near the end of their first closed beta, upcoming MMORPG Elyon GMs showed up on big dragons and gave players a bunch of mounts and things.
Check out https://www.twitch.tv/shardentv for live streams of the closed beta 2 (CBT2) and a chance to earn access via drops.
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I can't remember the last time I played a new game where a GM was actually present. This is exactly how it is supposed to be.