What you can respond to is effects that cause a coin flip to happen in the first place
Orvar has been around for such a long time that he has learned to use his powers in more creative ways
Toski, Bearer of Secrets Speaking of Squirrels, let's all give a warm welcome to Toski, Bearer of Secrets, a 1/1 Legendary Squirrel that can't be countered, is Indestructible, has to attack each combat if able, and, perhaps most importantly, lets you draw a card whenever a Creature you control deals combat damage to a player
This sort of card usually needs a build around grade, because if you dont have enough ways to go really wide, you cant really play it but when youre in the right deck, this ends a lot of games This has bad base stats, but at least it can buff itself in a pinch
The bane of white-blue decks in that format was Cabal Torturer, and without Psionic Gift, the only good way to deal with this creature was to splash red or black as a third color, weakening your mana base
The exhaust ability youll want to use first is the four mana one that nets you a 4/4 Dinosaur Dragon creature with flying, which is a pretty good when you have nothing else to play once you hit four mana