Bannerhide Krushok
Creature — Beast
Trample
Reinforce 2—
(, Discard this card: Put two +1/+1 counters on target creature.)
Scavenge 
(, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)
Joe Slucher
Modern Horizons 2 (MH2)
• #149Rulings
If you activate Bannerhide Krushok's reinforce ability during your main phase, your opponents will have the chance to respond to that ability before you can activate the scavenge ability, perhaps by removing Bannerhide Krushok from your graveyard. However, if Bannerhide Krushok ends up in your graveyard during your main phase in such a way that there are no spells or abilities on the stack, you'll have priority to activate the scavenge ability before anyone can remove Bannerhide Krushok from your graveyard.
(wotc • 2021-06-18)
Exiling the creature card with scavenge is part of the cost of activating the scavenge ability. Once the ability is activated and the cost is paid, it's too late to stop the ability from being activated by trying to remove the creature card from the graveyard.
(wotc • 2021-06-18)
Rulings
If you activate Bannerhide Krushok's reinforce ability during your main phase, your opponents will have the chance to respond to that ability before you can activate the scavenge ability, perhaps by removing Bannerhide Krushok from your graveyard. However, if Bannerhide Krushok ends up in your graveyard during your main phase in such a way that there are no spells or abilities on the stack, you'll have priority to activate the scavenge ability before anyone can remove Bannerhide Krushok from your graveyard.
(wotc • 2021-06-18)
Exiling the creature card with scavenge is part of the cost of activating the scavenge ability. Once the ability is activated and the cost is paid, it's too late to stop the ability from being activated by trying to remove the creature card from the graveyard.
(wotc • 2021-06-18)