Chaotic Gore Magala

Sacrifice a creature named "Gore Magala" : You
can cast Chaotic Gore Magala for {w}{b}.
{1}{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).