Toxic Deluge is the premier black board wipe, being the cheapest at 3 mana, but it does come with the drawback of having to pay life to remove everything
Brawl Not Legal Vintage Not Legal Timeless Not Legal Commander Not Legal Pauper Not Legal Oathbreaker Not Legal Penny Not Legal Chandra, Dressed to Kill Emblem Emblem Whenever you cast a red spell, this emblem deals X damage to any target, where X is the amount of mana spent to cast that spell
UB is a strange color identity for a sea creature deck, but Runo presents a fun mini-game to get it flipped, and Krothuss, Lord of the Deep is one of the best sea creature payoffs you could ask for
Slab Kings Plus gives you both
My friend, cant start a game with that deck until my match is finished
What about design