1 Mossfire Valley
Round Up Requisition Raid | Illustration by Viko Menezes Yee haw
In games where you dont draw Violent Outburst, jamming Oko, Thief of Crowns can help you pull ahead
Something about the card that is rather bizarre though is the fact that in its original printing, your opponent calls the call flip whereas in most other printings, you call the coin flip
The end result is that The Ur-Dragon plays a "fair" game of Magic, winning all sorts of ways with lots of variety, while Scion of the Ur-Dragon is a hyper-consistent "unfair" deck looking to 1-shot opponents, combo off, or cheat tons of Dragons on to the battlefield
Essentially, this card means every permanent spell cast makes one of your creatures bigger, producing a rapidly escalating threat