Murky Depths

Whenever a creature an opponent controls attacks, it gets -X/-0 until end of turn, where
X is the number of attacking creatures. That opponent may discard a card to ignore this effect until end of turn.
"What sets us apart from the other sirens of Theros
is that they seek only to feed. I endeavor to fulfill, to grant belonging, to empower. They want one meal,
I want an empire."
- Saorise