I really like the artwork... its a little disturbing for a
card, but very cool nevertheless.
Getting to the mechanics and theme...
I think I get where you're going with this, but the wording is a bit confusing.
So basically:
whenever a hostile effect is applied to a permanent owned by this cards owner, it will also be applied to a permanent owned by this card's owner's opponent as well... is that correct?
... if so, maybe something like: "Whenever a hostile effect is applied to a permanent you own, it is also applied to an enemy permanent if possible." would be a little more clear.
...Or, do you mean for this to include creatures and / or cards in hand or deck as well? If that is the case, just use the above, bur replace "permanent" with "card" instead.
At any rate, I like the concept, though it is certainly a very powerful effect. I think it may need some kind of counterbalance built in to avoid being OP.
Maybe a limited duration
e.g. "Whenever a hostile effect is applied to a card you own, it is also applied to an enemy card if possible. Lasts 3 turns."
or double-edge type mechanic of some kind.
e.g. "Whenever a card is targeted by a hostile effect, that effect will be applied to a card on the opposing side if possible."