Gore Magala

{2}{b} : Put a "Virus" counter on targetted
creature.
At the beginning of your Upkeep, increase every
"Virus" counter by 1.
If a creature has 3 "Virus" counters, remove
them. This creature gets -0/-X, X being half of
its toughness (if its toughness is odd, X is half of
its toughness -1).