Mechadragon

The mechadragon was created by Gaius and Gwen, and given to Merlin who modified it further. It can be used as a UAV, as well as being sent files to that can be downloaded onto a computer, and speaking messages. It understands commands in Welsh, too and has a surprisingly humanoide and round personality.
(Art of the mechadragon as drawn byhttp://emmaehrling.tumblr.com/)
Stars in the Extra Advance Warning
==Quotes==
“Message from Merlin to Arthur,” the mechadragon said, its synthesized voice a low, purring hum. “Come and get me, Captain Prat. Forty-five minutes from now. I’ll have company — you probably already know one bloke. There might be another. I’m not sure. Love you. See you soon.”(Collaborations)
“3:40:04,” the mechadragon said. “New message for Arthur from Merlin: You’re probably getting everyone to check in by now. So this is me, checking in.” (Collaborations)
==Hive Speculation==
It's the universal head-canon that the mechadragon is actually called Aithusa. The jury (aka Footloose) is still out on that, though ...