Its great as part of a combo deck with Dualcaster Mage and Neoform in Constructed formats or paired with many, many cards in EDH and other eternal formats
Even with these additions, Death Toll is a little light on spells that reset the board
On top of a sweeping +1/+1 counter effect, Fluttershy can take a key creature out of the equation, so long as you're able to keep your eyes on it
However, I do think making your opponent lose 3 as well is a significant upgrade, but it still might be too slow This seems like a solid Common
Granted, there are practically zero penalties for losing, so theres no reason not to just concede and hope for better luck next time, but that random element seems to end most games before they can even start