Azrel, Singing Maelstrom

+1: Create a 1/1 red blue otter token with prowess.
-3: Cast an instant or sorcery from your hand with mana cost less than half the otters you control for free.
-7: Create an emblem with "Each turn and whenever an instant or sorcery has been cast, create a 1/1 red blue otter token with prowess."