You decide how to distribute the stun counters as Crashing Wave resolves, and you can put the counters on any tapped creatures your opponents control, not just creatures tapped by Crashing Wave
Seafloor Oracle turns all of your Merfolk into Scroll Thieves, so the potential card advantage gained is incredible if you are able to connect with even just two or three Merfolks with Seafloor Oracle on the battlefield
Credit: Wizards of the Coast Molten Duplication Marcy: There were already combo decks using this in Standard during the pre-release events that kept copying Trumpeting Carnosaur, so I think it is fair that you can expect to see this card popping up in combo decks, except maybe just not in Commander, where I think a singleton copy of this card dilutes the power of it
Goblin Matron looks poisonous, but totally isn't
Dargo, the Shipwrecker I'm not sure Dargo, the Shipwrecker realizes how special seven power is in commander
The ability you need to prevent blocking and damage is protection, which prevents creatures with some specific quality (usually a color) from being able to block, damage, and basically affect the protected creature in any way
