Mainly, 2 mana makes it really cheap to cast and it triggers whenever you attack with a merfolk, which is really easy to enable
Additionally, each deck has a planar die, so you have a fresh one you can use to bop around planes
Vessel of Nascency: if you have scryed before, say, in Modern, then activating this card will be really good
Cards that Take Advantage of Sacrifice To get the most out of the creatures dying on the board, this deck plays creatures like: Tergrid, God of Fright is one of our 99 cards, though she is also one of the most hated Commanders in the community, particularly by casual players
That said, you do get to decide when you play it, and casting it in response to a creature with an ETB or something is likely to feel pretty good