Phyrexian Ritualist

Whenever a -1/-1 counter is put onto a creature
an opponent controls, that creature gets +2/+0
and Infect, and you gain control
of that creature until your next turn.
{4}: Put a -1/-1 counter on target creature
{b}: Target creature gains Infect until end of turn.
One way or another, everyone joins the Orthodoxy.
-Elesh Norn, Grand Cenobite