The problem with playing reactively against both cards is that theyre so mana-efficient and provide some inherent value, and having a one-cost unstoppable answer to both helps a lot with that
Its certainly much pricier than Underworld Connections, both in terms of mana and life, but the ability to trade life for cards is very valuable when you have Gray Merchant in your deck, even if the rate isnt the best
Now, the shenanigans: Combine with a creature like Neheb, the Eternal or Savage Ventmaw, then chain together extra combats by filtering the mana they produce through Aggravated Assault activations
Mascot Pokmon often market for decent prices, but Rapid Strike Urshfiu VMAX also has the gameplay utility to justify it
House Greyjoy Ability: Crew The Greyjoys were an easy choice for ability, they do love their ships so the crew ability is the ability for them