Assimilated Karn, Oil-Host

Whenever Assimilated Karn, Oil-Host attacks you
may have him become a 1/1 with Indestructible
until the end of the turn. If you do, it fights another creature. If that creature survives, it gains an oil
counter.

Essence - Alien creatures you control gain +X/+X,
and non-Alien creatures you don't control gain
-X/-X, where X is the number of oil counters
on them.