Mishra, Eminent One is a mythic Legendary Creature — Human Artificer card from Magic Online Promos (PRM), collector number 105804.
At the beginning of combat on your turn, create a token that's a copy of target noncreature artifact you control, except its name is Mishra's Warform and it's a 4/4 Construct artifact creature in addition to its other types. It gains haste until end of turn. Sacrifice it at the beginning of the next end step.