The Sentinel

Flying, First Strike, Indestructible, Shroud
As long as you control less than 5 artifacts, The Sentinel isn't a creature.
"They said it was the guardian of Xerxes. They said it could take the form of a dragon, a beast, a snake, or a human. They said it could slay gods. They said it could shoot lasers from its eyes. What they forgot to say is that it's rusted to Hell and hasn't moved in decades!"
--Darnon Stonecrusher, Frustrated Xerxian Engineer