Makes me think of the Cheshire cat.
Maybe it shouldn't be able to target the Mark, as it is kinda immortal.
And I hope immortal cards can't be targeted either.
It's something that darkness would do. Mini weak Nightmare and giving the opponent a pretty useless card.
For the cost, I think the up version should still use two darkness to hide. And also, you need to specify which seek the owlcat will generate.
With one pest, this will cause the -1(Owlcat 4, opponent 3) into +1 (Owlcat 3, opponent 4). Brilliant.
One other thing, Silence will match this card pretty well.