I have two of these in my U/W Merfolk deck. Seahunter is always great for bringing him out if I don't happen to draw him. Of course, he has great synergy with Master of the Pearl Trident blah blah blah.

However, my favorite part is when I use him to cast Gisela, Blade of Goldnight. Such a random combo, it always manages to throw my opponents off balance. 4/5