The full teaser trailer was posted before being pulled down
The only pure Sea Serpent archetype is Atlantean, which is often paired with Mermail
Most secondary Commander products, like the Zendikar Rising or Kaldheim decks, consist of only two decks
But its real purpose is its other ability: Whenever a creature an opponent controls is dealt excess noncombat damage, amass Orcs X, where X is that excess damage. It can be a great source of Amass Orcs and it is a part of a 2 card combo with Blasphemous Act that results in near-infinite +1/+1 counters on an Army token and near-infinite damage to all creatures
While toughness is typically a measure of a creature's defensive ability, the printing of cards like Assault Formation, which allow creatures to assign damage equal to their toughness, has made these creatures sought after for toughness-themed decks
The best quick play spell is Runick Tip due to the sheer versatility of the card, and it reads as follows: Activate 1 of these effects, but skip your next Battle Phase after activation