Thrashing Mossdog

Reach (This creature can block creatures with flying.)
Scavenge {4}{G}{G} ({4}{G}{G}, 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.)

Ravnica: Clue Edition

Reach
Scavenge {4}{G}{G} ({4}{G}{G}, 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.)

Dragon's Maze

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.