With its ability to trade against multiple creatures as a 0 mana 2 for 1 effect, it wont become dead in later stages of the game due to being a castable threat itself
With both in play, youd create a mutagen token every time a creature leaves the battlefield, along with a food token and +1/+1 counter on a single creature every time you attack
Its been impactful in many formats, to the point that playing 20 more cards in your deck just to get the companion mechanic going seems like a good idea (sorry Commander players, you cant have a 120 card-deck)
This thing loves blink and midrange that loads down decks with ETB stuff as well the needed triggers of dying things in Aristocrats and Sacrifice-matters, Artifact decks, even a Solemn Simulacrum that most run is quite doable
#4: Grindstone Price: $16.87 A classic mill card that can be used to pitch your own cards directly to the grave or whittle down your opponents libraries