Reaper, Gift of Oil

Shroud, Toxic 4
Whenever you would put counters on a
permanent, you may have any number of those counters be oil counters instead.
At the beginning of your upkeep, gain control of
all permanents with oil counters on them. They
become phyrexian in addition to their other
types.
Creatures have toxic X, where X is the number
of oil counters on them.