A short Level Up moment: Playing at instant speed means leaving mana up, and a good way to protect your investment is to have access to a mana-sink. Even if your opponents don't play a spell worth countering or a permanent worth destroying, you can still spend your mana to take other game actions, and Thrasios, Triton Hero has made his name as one of the best partners in the game precisely because he's such a good mana sink!