Clank!: Sunken Treasures

From BoardGameGeek:

In Clank! Sunken Treasures, an expansion for Clank! A Deck-Building Adventure, players explore two partially flooded maps with new dungeon deck cards, a new persistent monster to defeat, new environmental challenges, and more as they venture in the watery depths! The challenge to prove your thieving skills has moved to new environments. You'd better know how to swim as several rooms you'll face have been completely flooded with water. Plus, of course, there's always an angry dragon to avoid...