To find this mob in-game, use BACKSPACE to open the World Search window, then enter Owenstein in the Search field and click "Search". Remember, the field is case-sensitive and must be entered exactly as shown.
Following the Anniversary Celebration in 2016, Celebration Certificates continued dropping in the Mirrorworld Instances. To give us something to do with this largess, They outfitted the Event Hosts to swing into action. See Celebration Certificate for more info.