Wave Scrambler 2000 used to summon The Underpin inside a delve for a 
Delver’s Bounty that guarantees a Hero-track loot at the end of your run, shouldn’t be used in underwater delves, and here’s why.
Difficulty and Pathing Issues
Not only is it difficult to dodge The Underpin’s abilities and bring him down to 50% underwater, but you’re going to run into pathing issues where you can’t loot the pile of gold that spawns. Reddit user lio-ns speaks from their own experience:
Unless you want to waste your Wave Scrambler 2000, don’t use it in an underwater delve.
byu/lio-ns inwow
As you can see, the player couldn’t reach the loot pile, and the Delver Bounty wasn’t mailed to them, just 128 Undercoins were. So next time when you run an underwater delve, don’t waste 2,000 
Undercoins!
Instead, choose a simple delve like Earthcrawl Mines when it’s up. Don’t forget to clear the area after the checkpoint before using Wave Scrambler 2000.
