Bayou Groff
Creature — Plant Dog
As an additional cost to cast this spell, sacrifice a creature or pay 
.
"Groffs are great for tracking pests through the muck, but securing the pests before the groff devours them is a dicey endeavor." —Lisette, Witherbloom dean
Ilse Gort
Rulings
Players can respond to Bayou Groff only after it’s been cast and all its costs have been paid. No one can try to destroy the creature you sacrificed to stop you from casting this spell or to make it cost more mana.
(wotc • 2021-04-16)
You must sacrifice exactly one creature or pay an extra {3} to cast this spell; you can’t cast it without paying one of those costs, and you can’t pay either multiple times.
(wotc • 2021-04-16)
Rulings
Players can respond to Bayou Groff only after it’s been cast and all its costs have been paid. No one can try to destroy the creature you sacrificed to stop you from casting this spell or to make it cost more mana.
(wotc • 2021-04-16)
You must sacrifice exactly one creature or pay an extra {3} to cast this spell; you can’t cast it without paying one of those costs, and you can’t pay either multiple times.
(wotc • 2021-04-16)