If this creature's controller can prevent it from being blocked and can put at least one merfolk into play each turn, it can effectively be used to chain countless turns together, winning the game for its controller
According to PriceCharting, however, one PSA 10 graded version of the card sold for $12,000 at auction in 2021
Much like many other alt arts, this card catapulted up to the $95 range before dropping by over 20 percent into the mid-70s
What makes them good is that they deal with most of the problems you might face, be that a Baneslayer Angel, a Sword of Fire and Ice or a Moat (well, not Abrupt Decay but you get the point)
Unique Crossover : Combines the rich lore of Warhammer 40,000 with the strategic depth of Magic: The Gathering